I didn't really watch it as a music Anime, but just as pretty much a comedy filled with fan service and moe moments. I don't think K-On! really needs a serious analysis. Just take it for what it is. Some might find the jokes funny, others not. Some might love the moe momments, others may hate moe blobs.
I actually liked the subtle character and simply character development in Yui. She found a direction and purpose in life, yay. I didn't really get why Yui got so much hate. I thought that... crap forgot the names already, the basist was acutally the moe blob, rather than Yui.
Half of Yui's moe stuff was non-serious (such as when they were trying to decide who was going to sing, between Tsumugi and Yui).
It's a short sweet series (is there going to be OVA's or something?), and I think that it doesn't really deserve all the hate, but shouldn't really be lauded as some master piece.
