Who's Gunn now? I'm bad with names. That the leader of the vampire-killing vigilantes?
The first slayer was, like the Indians on the Thanksgiving, kinda racist-y feeling, but it confirms the implication laid out before that slayers are super-ancient. I think you did say they'll explain the slayer origin story, but if I had to guess it's some sort of Angel-like monster or vampire turned "good" somehow, like maybe Buffy is 1/1000th vampire.
Or maybe Willow is... during her dream people kept talking about how she's hiding who she really is. At first I thought maybe they were talking about the gay thing, but that's already out... then I thought maybe the witch thing, but they know that (given how TV is, I'm sure Willow will become the bestest most superpowerful witch ever ever, so maybe she has some slayer-like genetic thing in her). But then they "reveal" that it's her identity as a nerd in high school. Um...what? Since when is she ashamed of her geekdom? Or am I missing something? Willow's dream was fantastic up until the very end.
"Since when is there a cowboy in Death of Salesman?"
The spell that helped defeat Adam was weird... so they joined strength but also harnessed the power of previous slayers? Huh? And then Adam's ridiculous machine gun hand. I was too swept up in the action to think about it while watching but on retrospect it's all quite silly.
And that pretty much defines the season. Many great moments held together by nothing.
And it's the themes and characters too- like Spike trying to split the group with gossip, and they so easily believe him. That whole thread began and ended so abruptly. But it also gave a couple of my favorite moments- the look on Spike's face when he understands Willow and Tara's relationship and immediately plans on using it to his advantage. And Buffy's line about how "there's no ancient prophecy about a chosen one and her friends." Ouch. Awesome stuff.
And then Angel comes back to fight a little, say sorry, then leave. Superfluous. However I will guess that from now on we'll see much less cross-over between the two shows, now that Angel (the show) has had a chance to establish itself.
It's not a bad season by any means- anything with that many great moments and individual episodes that are amongst the best of the show (Hush, Restless). It's just not as cohesive and "organic" as the previous 2. I think this is due to trying to do so much- expanding the world of demon-fighting with the government and military, AND they're in college instead of high school AND everybody is trying to figure out how to navigate new kinds of relationships AND lets also try to split them up AND Angel AND Faith. Trying to juggle all of these things forced them to set up conflict like: here's a problem with potential solution; now here's the solution. Nothing gets to simmer in my brain enough to have the full impact of previous events.
When Adam died, did anyone think anything other than "cool, and that's weird that it's not the last episode." But when the mayor died, it's "wow, they had to blow up the school to do it, and how is it going to effect the whole town and omg Faith" etc. There was more to it than just "villain defeated." Or when Xander was feeling left out in The Zeppo, there was a long build up to that that made it understandable, and a clever and fun-to-watch solution. This time, it just feels like a retread, added just to give him something to do. Or Willow being angry that Buffy "freaked" about Tara- but she didn't "freak," she was surprised, wtf is Willow so mad about? Other than Oz's return, she really had no reason to be all angsty and conflicted and buy Spike's bullshit so easily.
Oh Spike still has a chip on his head, and the Initiative is over. So I guess he's gonna be around a while. I hope they don't render him completely harmless and he learns to love Buffy and her friends... now remembering the dream part about him being Giles' "son"... and also Buffy calling Xander "big brother."
The military imagery around Xander continues. He might actually join the army at some point. In the dream bathroom there are all these military guys, and an Apocalypse Now parody, and it just keeps coming up in some form.
I read that season 5 is universally loved, so I look forward to that.