I'm going to reply to a couple of posts which I think sum up the situation.
I know I've wondered about Giles and his decisions more than a few times.
They do have a human and Buffyverse quality to them of not always being up to snuff.
His actions, actually, make me believe that the council was right to fire him because he IS acting more as a Father than a Watcher.
Yes, I do think he did abandon the Watcher role in lieu of the Father-figure role.
Even Buffy states that she needs him to be her Watcher again. I don't think he took up the role again without the father-figure as duality and coloring his decisions. Which is not what Buffy needed or asked for.
Beyond Buffy, I think it wasn't necessarily RIGHT, as a watcher or a father, to leave when Buffy was dead. To just leave all those "kids" that he'd grown to love there and worked with for years knowing the danger was still around and that Dawn could be taken at any moment and rushed off to foster care was a little weird and out of character. He had a business there and as a friend, and the only really authority figure these people had, a responsibility to stay and help fight the evil lurking around the Hellmouth.
As a Watcher, perhaps. There is evil in the world everywhere. In that part he did seem to go off and expand his own strengths in magic, or at least hooked up with others who could help him. So perhaps there was a bigger picture going on there.
As a father-figure to Buffy, there is a certain an abandonment issue as to how far that extends to friends. He knew full well what path Willow was treading on and pretty much knew the eventual outcome. If he left to gain more magical ability to stop her then it was a wise choice. I doubt Willow would have listened to reason from him, she couldn't even when it came from Tara. As for the Hellmouth, well there are a few of those. They were adults after all.
Giles' decision to conspire with Robin Wood in an attempt to kill Spike could very well have cost Buffy and her friends the war and meant world wide chaos at the lest, and total destruction at the best. Granted, he didn't know that at the time, but he still should have had enough faith in Buffy's instincts not to have betrayed her in that way, and that's exactly what it was: betrayal.
And where a clear instance of the Watcher/Father-figure conflict worked against him and everyone else.
It almost appeared that he abandoned both in favor of dispassionate analysis - Black/White and held his charge's opinions as unworthy.
Spike was evil/vampire and half crazy. Spike had a trigger usable by The First. Spike should be dusted.
He utilized neither the Watcher persona or the Father-figure persona with Buffy except in misdirection.
While he obviously never did agree even from the beginning with Buffy's choices regarding her vampiric acquaintances, and lives were lost because of Buffy's belief, in the end for each there would have been even more life lost than not had Giles done what he thought best.
Hopefully, Giles would have used those examples to completely re-think his feelings ... but his actions in dealing with Angel when he asked for help while Fred was dying would seem to indicate that he is the same old Giles.
Yes, the Black/White attitude was still prevalent. Wolfram & Hart bad. Angel evil/vampire.
I would say that perhaps something happened to him while away that completely colored his outlook.
Perhaps it was Buffy's death itself. It could almost be argued that after Buffy's first death (due to his strict Watcher training and reliance on prophecy) that he began to shed the Watcher aspect and then began to take the Father-figure persona which the Watcher council recognized. With her second Death, even that may have been shed in favor of something new. Non-colored dispassionate analysis.
