Season 6 was disappointing, not because it went to dark places, but because it seemed so forced. With the exception of OMWF, Whedon seemed to take a backseat to things (it's the only season in the run with an opening and finale he neither wrote nor directed). Dark Willow's finale storyline started out strong (running on pure rage from her murdered lover) and then seemed drawn out for the hell of it (turns out she's just a nerd who discovered drugs).
And don't get me started on dumb episodes like "Doublemeat Palace".
You're right about Whedon's absence for most of Season 6 (he was prepping Firefly at the time, as well as working on OMWF, which was a lot more work than the average episode), and S6 definitely has the weakest opening of any Buffy season. But I thought the finale was really powerful. I didn't start paying attention to who wrote or directed what until I started watching them on DVD, and when I got to that episode ("Grave") I was really surprised that it wasn't a Whedon episode.
Here's a question for everybody: What are your favorite and LEAST favorite episodes? It can be Buffy or any other Whedon show.
If I had to pick just one Buffy episode as my favorite, it would probably be Season 3's "Dopplegangland", when an alternate-universe vampire Willow (seen previously in "The Wish") is accidentally transported to "our" Sunnydale. Whedon at his best, IMO. Hilarious.
My least favorite is probably the "invisible girl" episode from S1. I just think that one is...dumb.
"What? Did your life pass before your eyes? Cuppa tea, cuppa tea, almost got shagged, cuppa tea..."
