Dwight's legend has always been rooted in the fact that he's a game-changing defensive force. Before this season, he's played minutes in the mid to high 30s for the past six years with the Magic, while never missing more than four games. During that period, the Magic were 6th, 6th, 1st, 3rd and 3rd in defensive efficiency. He's clearly a transformative figure on defense--always making a huge impact in team defense, as he has the lateral quickness (particularly for his size) and anticipation down pat, and needless to say with his build and athleticism he's an imposing figure to shoot over. His man defense is much the same way--he completely neutralizes the opposing starting center, severely snuffing out their field goal percentages and outrebounding them badly. He's rapidly improved his defense over the past several years, and as mentioned above, the results show team-wise--the Magic weren't known for having any good defenders at all besides Dwight, and he was able to single-handedly elevate the team on that end. You can count the number of players on one hand who are able to do that in the league. Dwight is one of them. He has three DPOYs under his belt to further validate that fact.
People always rave about Dwight's combination of speed, strength, and athleticism and say he's the most "ripped" person in the league, and that's obviously a big factor in his success. Where Dwight excels at is in clearing the defensive boards--over the past six years, he's absolutely been league-leading material in this end. He's the best in the business at forcing misses and then clearing the subsequent board--this is important because too often we see bad rebounders/defenders who go for every block, or guys who don't bother contesting shots who go for every board. Dwight does both, and for 34-38 minutes a night. Because of this, over the past six years, he'd be in the top one or two in overall rebounding among centers. Dwight's defense and rebounding are absolutely transformative aspects of his game--he's arguably the best in the business right now on those fronts.
Dwight's defensive playmaking numbers have tailed off a bit, particularly in the shotblocking front, but over the past several years he's jumped into the top six-eight among centers in steals--he's developed quite a nose for poking at the ball. He's still a good to excellent shotblocker, however, needless to say with all those highlight reels populating youtube. Ironically, for a Lakers team that is severely lacking in steals, he might actually be one of the major pluses on that end. On the whole, he's in the top seven-twelve among big men in making defensive plays. However, unlike many of the big men above him in defensive playmaking, Dwight ranks the highest in defensive plays/foul ratio, so he knows how to judiciously make defensive plays without jeopardizing his minutes on the court (the only one who is better than him in that is Ben Wallace, although Chris Andersen is in the periphery). Needless to say, many of those big men play minutes from the low teens to mid 20s, as a result of their foul trouble. So even Dwight's reduced defensive playmaking can be construed as a positive. But defensive playmaking is useful only if it is coupled with the actual defense and rebounding, which as mentioned above, Dwight is absolutely the cream of the crop in this area. Coupled with the defensive discipline he's shown in the past few years, that makes him an even bigger factor. Only six centers, including now former Laker Andrew Bynum, average fewer fouls per minute, but Bynum didn't rebound as well as Dwight nor did he play defense at that level either.
Again, with the exception of this season (which we'll talk about later), Dwight's offensive efficiency for a big man is top five material, and what's more is that he creates these shots on his own accord (five of the past six seasons, he was in the bottom five in shots assisted). Dwight's a good offensive rebounder, but not even as close as good as he is on defensive rebounding (which speaks to how great that attribute of his game is), so he isn't always just getting tip-ins. Dwight's more than just a catch-and-dump player in the post--he's good at creating his shot there, even if the way he gets off his shot doesn't look completely orthodox as say, Andrew Bynum. He's always largely been in the top five in finishing around the basket, and is an extremely prolific dunker who always ranks in the top five in dunks per 48 minutes every season. He's never averaged less than two dunks a game since his rookie year, and by and large he's the most prolific dunker since Shaq, and this is another area where he bests Bynum in. He also made the most AND-1 plays the past year, and ranked second in AND-1 percentage, which is not a surprise as he can easily finish through contact. Also, he ranked first in the league as the roll man in pick-and-roll plays, and considering Steve Nash led the league in pick-and-roll passes this season, this is a pairing made in heaven, and can see Dwight get more than his average in dunks as a result. Of note is that Dwight's 2008 season saw more of his shots assisted far more than his norms, and as a result he shot significantly better at the rim and drew more fouls. So there's precedence that Nash can improve those areas.
The path of lesser resistance is to foul Dwight given his high finishing ability around the basket, and that's what teams do--he's mostly in the top, sometimes second, in free throw drawing over the past half decade. It's a way better proposition to have Dwight shoot 58.8% from the line (his career average) rather than consistently finish at 74% around the basket. But even though Dwight's prone to getting hacked at the end of close games, getting to the line is still an easy way to manufacture points, and it comes with the bonus of getting opposing frontcourts in foul trouble, which Dwight is the best in the business at doing.
There is a common misconception that Dwight is super turnover prone and that he's easy to strip the ball from--and many teams use double teams largely to force turnovers in this fashion. He's been above the league average for centers several times over the past decade, but also been below the average several times, such as this season. He isn't as bad a ballhandler as many would like to believe, and he's actually made inroads in this area. Among centers with usage rates above 20, Nene, Derrick Favors, Chris Kaman and Tiago Splitter were worse this season.
Where it's easier to criticize Dwight on is his passing--he's oscillating between very bad to bad, but still he's definitely subpar after eight years in the league, and for that usage rate it stands out. That's also a reason teams double team him, because he can't find the open man, and teams wish that it would lead to a turnover rather than a forced shot. But the reality is, there are quite a few big men playing in the 20s in minutes who don't pass the ball well and accrue turnovers at a similar pace (JaVale McGee, Marcin Gortat, Derrick Favors, Andrew Bynum to name a few) and they all contribute in various ways, so this issue isn't as big as it should be made to be. As a roll man finisher, he wouldn't need to think and hold on to the ball as often, so issues like this would be less important as well.
Howard's game is largely centralized within 10 feet, and he virtually will never take a shot beyond that, so he knows is limitations (as seen by his free throw percentages). He's steadily increased his shot attempts from that range--about 2/5ths of his shots come from there, well above the norms for most centers. Roy Hibbert, Al Jefferson, and Andrew Bynum take as many shots from this distance and hit them better, but Dwight hits them at a pretty good 41-44% clip, above the average for centers, which helps to optimize his post up game. He also creates quite a few of these shots for himself as well, so he has an assortment of moves here. Overall, between his prolific and almost-indefensible-without-fouling at the rim game and an underrated 3-9 foot game, he's quite underrated offensively, even if aesthetically he doesn't look as smooth as many offensive-minded centers. But still, he gets it done, and has elite attributes (dunking/free throw drawing) that no other big can boast of, and which gives him a big advantage. In the mid to late 2000s, he's also posted very good offensive +/- numbers, so he's capable of being a first offensive option.
In a league where big men are most prone to injuries, Dwight played all 82 games in his first four seasons and never missed more than four games for his next three--he was as close to an "iron man" in this league as anyone, between his ability to stay healthy and his physique. He had back problems and subsequent surgery this year, but still, his track record for health still appears to be very good, and on top of that he's staying on the floor better (reducing fouls while maintaining his defense).
Dwight's demeanor may be a bit of a concern. He got injured this year, yes, but there were complaints that he was coasting because he wanted to be traded--the Magic's D only ranked 13th this year, largely because Howard wasn't applying himself. Also, Howard wasn't as active blocking shots, wasn't drawing as many fouls as he did in the past, and also he shot a career low from the free throw line (49.1%) within the past six years, which reduced his scoring efficiency from years past. So there's that factor that when he's dissatisfied, he won't fully apply himself, although before that he was rapidly improving (particularly on defense) and not really regressing in any factor of the game, so this could be a one-time blip. He is quite immature, though, although with the daily beatings he's taking on offense (he's first-second in free throw rate in the league, with a top three-four usage rate as mentioned) he's taken to retaliation against the refs a lot--he's had 58 technicals over the past four seasons, which is definitely on the excessive side. Still, he's personable and charming, is always seen with a big smile on his face and you can tell he loves the game and means it (seen by his improvements) and doesn't have any real off-the-court baggage.
What this all means is that Dwight is just indecisive, petulant and immature when the going gets rough. He won't bring it on the court as hard, and his indecisiveness really put Orlando's management in a state of flux, leading to the firings of their coach and GM. Dwight essentially held the organization hostage to his whimsies. He isn't exactly egotistical, but he seems to be trying to explore his newfound power in free agency to the fullest, but he doesn't exactly know how to handle it. The Magic really seemed to lack a steadying presence, whether in the form of management or players, and appeared to have coddled him too much. The Lakers have a lot of alpha males and while it will be interesting to see how Dwight reacts as a likely reduced offensive option, but at the same time the Lakers have many vets who can react properly if Dwight starts to show discontent.
In the aggregate, Dwight is an absolute game-changer on defense, both being elite in rebounding and completely changing the team's defensive culture by playing elite man-to-man and team defense. He's also vastly underrated on offense, with elite dunking/finishing and foul drawing ability, and an underrated game within 10 feet. He also has a nearly clean slate with health, and has made improvements in defense, turnovers and reducing his fouls. The only downside is the slight immaturity, but with so many elite attributes, he's definitely a superstar and likely HOFer when all is said and done.