Oh, like I say, the guy will occasionally bang out a good story, no question.
But... it tends to be when he first starts off with a given set of material and then he sliiiiiiiiiiiiiiiiiiides slowly into meta-nonsense and, as you pointed out, forced "Family Guy" type wackiness and other such punnery.
Hulk's gonna go to the future and meet Evil Old Hulk or... Supergirl's gonna meet the pre-Crisis Supergirl and they're gonna meet some other Supergirls or... Q turns out to be Trelane's father and the whole Star Trek whiz-bang gets retconned for that book or... Captain Marvel turns out to be his own son and then he fights a sister who doesn't exist or...
Yeah, that or Impulse thinks someone's crazy so he pictures a screw and a ball in a thought bubble.
Of course, I guess he WAS involved in the whole Babylon 5 thing which was like... if a bunch of Star Trek fans got together and said "Look, we love the whole IDEA of Star Trek but we'd really like something a bit more arcane and convoluted and nitpicky and continuity-dense and we'd really only want people to understand it if they've seen every episode in order three or four times. Thanks."
Which then begat Lost and Heroes, two more shows which everyone tells me are good but I clearly would not be able to get into without buying all the DVDs and starting from scratch. God help us with, like, the new Battlestar Galactica or "the Buffyverse". You don't just need a scorecard for those, you need... like... a scorecard and a decoder ring and that whirly-translo thing from "The DiVinci Code".