I agree with your issues with s7, & I don't think I'll ever forgive the writers for that.....I think all the actors contracts end after 7 seasons, so Joss should have known it was a possibility that some of the cast would want out & he might be forced to end it - I'd like to think that SMG gave him a head's up though
Either way, the priorities in s7 were completed skewed. It was the last season & there was nothing I want more than the see the show go back to the scoobies, they were the heart of the show & always had been