Point is, he's regarded as a great GM, which I don't think he is. At all. He trades away all his prospects and throws shitloads of the owner's money around.
The biggest role in the Tigers' success was the fact that the rest of the division was historically weak (and still usually won it by a game or two) and he was significantly out-spending his divisional rivals.
I'm glad for you that you're happy he's with the Red Sox. I'm happy he's with the Red Sox, too.
I don't think he's a great GM and I agree he's benefited from a fairly weak division. But four ALCS appearances and two WS appearances in a decade is pretty damn good, especially after nearly two decades of futility. His drafting has been pretty crappy though.
But I don't see why it's a big deal he's traded prospects if few of those guys have actually amounted to anything at the major league level. His worst trades were what, Cody Ross/Jurrjens/Matt Joyce? Fine players, but not stars. Devon Travis could turn into a damn good player, but Dombrowski got one of the best 2B in the league in Kinsler (swapping his contract for Fielder's, which is looking better on a daily basis). Tigers have gotten nearly twice as much WAR in Dombrowski trades.