My thoughts:

Oh no, the message aligment is now reversed! I can see why, as right-aligned text isn't particularly easy to read, but it's going to take some getting used to after 4,5 years of seeing the contact's messages aligned to the right. I guess someone will create a patch for it anyway.

I think the mosaic layout of the People application was both better looking and nicer to use, it could have used some improvements but overall it was a great idea.

Otherwise, nothing to complain about, the UI changes in the Clock application and such are for the best. A very solid update overall that was worth the wait.