I actually found season 4 to be the weakest of all the seasons. In fact, it was the only season to NOT make a lasting impression on my mind. Season 7, perhaps, was only ’weak’ because Joss and the writers had to cram so much into so little episodes. Each episode held too information, too many unanswered questions; but they had no choice. The show was ending and their story wasn’t even close to being finished. One reason why Spike was shown a lot in that season was because they had to give us more information that would validate his move to Angel.
Xander had to be pushed into the background. He was the eyes. He watched. He saw. That was his role. Aside from his jokes, he couldn’t provide anything to counteract the First’s objective.
PodGiles? Give me a break. Going back to England changed him, granted, but he wa still Giles. Only more anti-Spike because of Xander and Robin. What he failed to realize is that a vampire’s war is with the Slayer and a Slayer’s war is with the vampire. One wins. Period.
SlutFaith has ALWAYS been SlutFaith. Spike didn’t change that, kiddo. Her being "a shadow of herself" had to happen. She was out of control. I would think her in AtS would be important, not something to dismiss.
Willow in AtS was always magic-oriented. in BTVS, they were trying to control that. Yes, I see the difference, but not in the way you see it. Willow had to heal, to deal. If she was bombarded with everything else in the show, she would die emotionally. Willow, at the end of BTVS, was her true self. She shone; literally, white hair and all.
The main characters were not shoved in the background ALL the time. Buffy had her ep, Dawn had hers, Robin had his ep, Spike had his, Willow hers, etc... To say that every ep was Spike-centric is to ignore the entire S7 and what it tried to do.
Joss had and tried to give each character their respective time and I admire that desire.
But even the JossGod himself can’t please everyone.