My problem with Boog is that he seems like a national announcer calling the Cubs on a daily basis. My perception is that he's very into the other teams, and doesn't seem nearly as into the Cubs. My other problem with Boog is that, honestly, he makes a lot of mistakes. Saying wrong players names, or the wrong count, or even the wrong score quite often. Lastly, I feel like JD has a great, subtle sense of humor, and the best thing to do as a partner is to let his jokes live hang out there on their own...or maybe slyly add to them after a bit. But Boog really just doesn't let that happen...he kinda hammers home JD's quips when they rarely need that.
That said, unless the Cubs could get Kevin Brown, I'm not really sure who else I'd want in there in his place.