Dwight Howard is poison. He's been poison to every team he's played for. He's very good at certain things, but he's probably only half the player he could've been if it wasn't for his poor attitude. He's never led a team to the promised land, and there's no reason to think he'll change his tune now.
I may be wrong because I haven't been paying attention to him in years, but Howard seems to have calmed down a LOT since coming to Houston.
I mean, back in the Magic / Lakers days you didn't HAVE to pay attention in order to hear stuff about Howard constantly. He did such stupid stuff that he just made his way in to the news on a weekly basis. It's not like that now, and I've barely heard a single negative thing about Howard the last couple of years.
Hard to believe, but I think he's grown up a lot.
I don't believe he's half the player he was either. Looking at his statistical production, he's still quite a beast by any other standards. 14 and 11 with elite defense is pretty impressive for an NBA big man - that's pretty close to DeAndre Jordan territory, and he's a VERY highly sought after guy these days.
The true value in Howard isn't what he can do on a nightly basis - though that is important. The true value is what he can potentially do come the playoffs. Howard even now, can still be downright dominant in stretches. He still has the potential to put up 30 point games, 20 rebounds games, 5 block games. All it takes is for him to have one of those nights in one or two crucial playoff game, and that could be the difference between making the finals or being a second round out.
It's also important to note that Howard is playing behind one of THE highest volume shooters in the NBA in James Harden, and that's reduced his role in a huge way offensively. He'd get more touches in Boston (Thomas isn't James Harden),and I still firmly believe that Howards scoring numbers would jump back up to at least around 16 a night as a Celtic. I think 16/12/2 is not outside the realm of possibility - maybe even more than that.
Howards ability to draw instant double teams on one end of the court, and dominate the paint on the end, would completely change the dynamic of this team. We'd have almost no flaws with him plugging up the middle - we'd be very, very hard to beat.