Did you just rate 4 and 7 over 2? Oh man, it's all gonna go off now.
There are good parts to Season 7, I'll admit that. The episodes Selfless, Conversations With Dead People, Lies My Parents Told Me and Chosen are awesome and then there are other good ones like Dirty Girls, but most are average at best (and a lot are far below that).
The writers just didn't know where they were going. I've never heard that actually said, but it seems pretty obvious. Just one example is the First's talk of the being an order (for killing people). At some point they just dropped that completely and gave up. So was the First being mystically forced to kill potentials first and slayers last, or was it jsut choosing to? It doesn't actually make sense to choose to, you don't leave an established slayer to train potentials when you could kill her and leave them floundering. Now you might be thinking that the First wanted the potentials out of the way so no slayer would rise, that it's easier to kill lots of potentials then a slayer than having to do it to slayer after slayer, one by one. But Buffy's died, therefore the First knows pretty much everything about her (hell, it seems to know pretty much everything about people who haven't died). Therefore, it knows that if Buffy dies, another slayer doesn't rise. Faith has to die for a new slayer to come along, we know this because there was no new slayer when Buffy died at the end of S5.
Anyway, my point is the First can't have been forced to go after the potentials first, because it just abandons that plan at one point, but it also doesn't make sense to follow that order tactically.
So many more things annoyed me (demons are having to choose a side, but only that one who dates Xander and the Uber-Vamps went with the First? Yeah right, listen writers, don't put a plot point in just to make one episode work and then ignore it for the rest of the season), but it'd take ages to write it all up again.
I agree with SSX though, that ideas wise, this could have been the best Buffy season ever (if only the Angel team had been writing it eh?).