65980, you've written a great post, I can see how much you care about this band just reading it, and I think you might be right asserting REM weren't the kind of guys to go for "the greatest band" title while U2 members are.
Well, you don't hit #1 on the US charts unless you're trying to be big, but I'm sure their early 90s success was quite beyond what they had expected.
I find Michael's vocal style and voice, which is very personal and recognisable, not very adaptable to different kinds of melodies, I find the band work a little stuck, that's why even if I like them, I wouldn't say I'm one of their fans.
Yeah, his voice is a weird thing. For me, it sounded tougher and had more 'integrity' in the old days, or maybe just the songs' production did. He doesn't have a great range, like Bono, but that voice is so ... unique, that it usually carries the day.
"Not very adaptable" might actually be a good way of describing R.E.M.'s only limitation -- they're kind of a more sophisticated, earthier Oasis; i.e., they do one thing very well. (In their case, classy guitar-pop.)