The fine points and flaws of the East's top three contenders

Dynasties often rule the NBA, but we're in an era of relative parity: we've seen four different champions and seven different finalists over the last four years. This coming season again features an uncommonly deep field of contenders. We're laying out reasons to believe in them and reasons to doubt them.

First up, the top tier of the Eastern Conference.

Milwaukee Bucks

Reasons to believe: Relative to the teams around them, Milwaukee had a quiet summer, bringing back basically the same squad that fell to the Celtics in the second round last postseason. But don't be too distracted by the shiny new objects dotting the surrounding landscape; at full strength, the Bucks were the best team in the Eastern Conference a season ago, and a healthy Khris Middleton might well have made them repeat champions. Even entering a campaign that will showcase big upgrades in Boston, Philadelphia, Cleveland, Brooklyn, Atlanta, and elsewhere, the road through the East still goes through Milwaukee, and through Giannis Antetokounmpo.

Antetokounmpo has stamped himself as the best player in basketball, with a singular ability to control the paint at both ends of the floor. He's still only 27, and continues to add dimension to his astounding skill set each year. After leaning into his play-finishing ability en route to the championship in 2020, he spent last season honing his post game, playmaking chops, and in-between craft. He also got accustomed to operating as the last line of defense, playing more center than ever to cover for the extended absence of Brook Lopez.

He brought all those skills to bear when he nearly toppled the eventual East champs in the second round, averaging 34 points and seven assists at one end of the floor while completely barricading the rim and vacuuming up rebounds to seal stops at the other. His brilliance alone allowed the Bucks to mount a valiant title defense, dragging the Celtics to seven games despite the absence of Middleton and a poor offensive performance from an overextended Jrue Holiday. With Middleton and Lopez presumably healthy entering the season, Milwaukee's starting lineup boasts more two-way balance than any team in the East.

The Middleton-Antetokounmpo two-man game can be the staple food of a robust offense while Holiday thrives as a secondary/tertiary creator. The Bucks' defense slipped toward the middle of the pack during the last two regular seasons, but they proved both years that when they dial it up for the playoffs, it's as impenetrable as any unit in the league. They have a bunch of different options to round out their starting five, which they can deploy situationally: Grayson Allen for maximum spacing, Bobby Portis for maximum size and rebounding, Wesley Matthews for optimal wing defense, or Pat Connaughton for a little bit of everything.

Milwaukee's offseason inactivity owed to minimal flexibility and a lack of realistic potential upgrades, but there's also something to be said for the power of continuity in an era where rosters constantly get reshuffled. This team has a proven formula, and the personnel to execute it at the highest level. Why try to fix what isn't broken?

Reasons to doubt: Though their franchise player is squarely in his prime, the Bucks aren't exactly a young team. Their second-, third-, and fourth-best players are 31, 32, and 34, respectively; two of their most important bench pieces are 36; and their biggest free-agent signing is 35 and coming off a torn ACL (Joe Ingles). Their depth beyond their top four is shaky, and there aren't many young players banging down the door to get into the rotation.

Middleton and Holiday haven't shown many signs of decline, but Lopez's age and health are real causes for concern after he lost nearly an entire season due to back surgery. For all of Antetokounmpo's disruptiveness on the interior, and Holiday's on the perimeter, Milwaukee's defense isn't remotely the same animal without their rim-protecting anchor on the back line.

Then there's that perpetual Bucks bugaboo to worry about: the half-court offense. Even accounting for Middleton's absence and the fact that they had to face Boston's incredible defense for seven games, it's unnerving that this team finished dead last in the postseason with an average of only 85.8 points per possession against a set defense, especially considering how that particular limitation has derailed their playoff runs in the past.

Milwaukee's shooting still feels sketchy - especially pull-up shooting, which is close to nonexistent outside of Middleton. Allen can help address that issue, but his minutes come at the cost of the team's defensive integrity. There's also a dearth of plus passers on the roster, despite Antetokounmpo's strides.

Two years ago, the Bucks' defense was good enough to overcome their offensive limitations. Is it still?

Boston Celtics

Reasons to believe: Defensive versatility is the most valuable currency in today's NBA and the Celtics possess as much of it as any team in the league.

Their big men can thrive playing at the level or in a drop; their point-of-attack defenders can slide up multiple positions on switches when they aren't artfully dodging screens; and their wings can guard up or down as need dictates. No player in their regular rotation can be targeted by mismatch-hunting opponents. They communicate and cover for each other as well as any team. On both an individual level and as a collective, they have almost no weak spots to exploit. That adaptable, airtight defense led the Celtics to the doorstep of a title, and it should be every bit as formidable this year once Robert Williams returns to the fold.

It was at the offensive end that Boston's championship pursuit fell apart this past spring, and the addition of Malcolm Brogdon should help address the team's major weak points. Brogdon, one of the strongest and most relentless drivers in the game, will provide a necessary dose of rim pressure for an offense that too often lacks a north-south component. He takes good care of the ball, which is vital for a team that turned it over on more than 15% of its possessions in the Finals. His spot-up shooting should boost Boston's 14th-ranked 3-point percentage, and his ability to excel on or off the ball will make him a seamless fit with a group that has plenty of mouths to feed and requires not only a steady hand but also a deferential one.

There are still limitations here, to be sure, but between Jayson Tatum (knocking on the door of top-10 status), Jaylen Brown (an All-Star-caliber wing scorer), Marcus Smart (a perpetually underrated playmaker), and Brogdon, the Celtics have four high-level creators in their likely closing lineup. Toss in the connective passing of Al Horford and Robert Williams, plus Derrick White's ability to extend advantages, and Boston should be able craft a worthy offensive complement to its championship-level defense.

Reasons to doubt: Even for a team with a clear identity and solid foundation, losing your head coach about a week before the start of training camp feels like a seismically destabilizing event. It's impossible to know right now how the sudden leadership change will affect the Celtics, or how the coaching philosophy and acumen of placeholder Joe Mazzulla (a back-bench coach until now) will differ from that of the suspended Ime Udoka. All we can say is it's a major disruption for a team facing enormous expectations.

Perhaps even more concerning is the state of Robert Williams' left knee. Boston's defensive anchor recently underwent his second surgery on the knee since tearing his meniscus last season, and after an initial recovery timeline of four-to-six weeks following the arthroscopic procedure, he's now expected to miss anywhere from eight to 12. The questionable big-man depth behind him makes this a precarious situation until he returns, and more so if he ultimately returns in a compromised state.

How much longer can 36-year-old Horford stave off father time? Can the 6-foot-6 Grant Williams hold up as a full-time backup center? Those are pertinent questions, because it's a steep drop-off from there to Luke Kornet. Regardless of who mans the five in Williams' absence, the Celtics will lack anything resembling a roll threat on offense and be pretty light on rim protection on defense. It's simply hard to win without a strong interior presence at either end of the court.

Philadelphia 76ers

Reasons to believe: Joel Embiid gives the Sixers a chance to stand toe-to-toe with anyone.

The reigning scoring champ and two-time MVP runner-up is a problem without an answer on offense; difficult to handle in space on account of his deceptively quick feet and remarkable mid-range prowess, impossible to guard in single coverage in the post due to his combination of strength and touch, and increasingly dangerous to double-team due to his improved court-mapping and passing ability. And that's to say nothing of his rim-blotting defensive presence. Even when operating at half capacity while dealing with a fractured orbital bone, concussion, and torn thumb ligament last postseason, he managed to will Philly back into its second-round series against Miami before running out of steam in a six-game defeat.

This year's Sixers surround Embiid with more offensive help than he's ever had. Even if last season represented James Harden's new normal as a scorer, he makes Embiid's life way easier with his passing and pick-and-roll craft. (The two of them ran a savagely effective two-man game even with Harden in his diminished state.) The ascendent Tyrese Maxey can pick up most of the slack on the scoring front, and a more decisive Tobias Harris looks to have settled into his role as a spot-up shooter and off-the-catch attacker. Standstill creation is a concern of the past: last year's Sixers finished fourth in half-court scoring efficiency during the regular season and fifth in the playoffs. We know what Maxey is capable of in transition. Any way you slice it, this team's going to pile up a ton of points.

The Sixers' offseason additions also give them legitimate depth for the first time in eons. Crucially, those additions should collectively provide an extra layer of insulation to a defensive unit that last season was held together by only Embiid and sometimes Matisse Thybulle, who struggles annually to stay on the floor in the playoffs due to his offensive limitations.

P.J. Tucker remains a rugged multi-positional defender who'll provide padding on both the perimeter and the interior without destroying the Sixers' spacing the way Thybulle does. Tucker also gives them a proper small-ball center option, something Philly's never really had in its efforts to answer the eternal question of how to survive with Embiid on the bench. They also added sticky-handed menace De'Anthony Melton to shore up the point of attack, and 3-and-D specialist Danuel House to fortify their wing depth.

They'll need circumstances to break their way for once, but there's enough here to win a title.

Reasons to doubt: At this point, the notion of a healthy Embiid in the postseason is something that has to be seen before it can be believed. Even accounting for the truism that nobody's 100% healthy by season's end, the extent to which Embiid is hampered each spring by some ailment or another is a pattern that's impossible to cast aside. Because without the big man operating near the peak of his powers, the 76ers will be nothing more than the second-round out they've been his entire career.

Point-of-attack defense is also still a major soft spot, despite the offseason reinforcements. Those new recruits might relieve a bit of pressure from the back line, but in crunch time it'll still be a Maxey and Harden perimeter, which is a troubling thought. Harden's sludginess defending in space is well documented, and Maxey - despite being far quicker laterally and a 6-foot-8 wingspan to help him corral opposing ball-handlers - has really struggled with the finer points of footwork and screen navigation. Embiid and Tucker can only put out so many fires.

In essence, the Sixers are built to overcome their defensive issues with a supercharged offense. But for that offense to actually be good enough to get them over their eternal second-round hump, they'll probably need more from Harden than they got last season (and especially last postseason). And at 33 years old with almost 38,000 NBA minutes on his odometer, it's possible the version of him Philly needs simply doesn't exist anymore. Maxey obviously has a bright future, but he's still only 21 and may not be ready to step into the role of No. 2 scorer on a contending team.

There's little doubt about how good this team can be, but there are a few too many ifs to feel confident about what they will be.