Funny that we've gotten to a point where people ask this kind of question about shows that I actually did see. Usually people ask about things from before my time.
I'll echo a lot of what has been said. I loved Spring Awakening a lot when I first saw it and for several years after, but now the flaws are starting to shine through a lot more for me. I LOVED the revival, though.
American Idiot is a very strange show for me, in that I really love it IN THEORY. I think the music and arrangements are excellent, and the staging and performances were also very strong. I actually saw the show 4 times, and every single time I thought I would like it more than the last time. I really wanted to like the show as a whole, but all 4 times I found it somewhat lacking. I guess it must have been the book, as others have said. But in hindsight I don't think the book was really that atrocious. The plot was thin, yes, but usually I'm not bothered by that in other shows. Oh well, it was what it was, I guess. I still really enjoy listening to the cast album.