Angel has already used the "make the day g away and everything will be all fixed again" trick twice, and it was nothing more than a crutch both times. Then there's "It wasn't REALLY me, it was mean ol' Angelus," and now mean ol' Angelus has become evil ol' Twilight.It's time for Angel, or Joss, to try something new, like, maybe, Angel accepts the fact that, because of him, Giles in dead, and dead in a no magic world means gone and ain't coming back. And, as far as that goes, what about the several thousand other people whose deaths Angel, as Twilight, is responsible for? Sure, Giles was special for Buffy, but that should in no way single him out for resurrection ahead of all of those other people.
And as for Whistler plotting to dust Angel, why not? Maybe the PTB figure that he's done about as much damage as they can manipulate him into doing, and it's time to break in a fresh puppet.
I'm sure that, ultimately, it's all for the greater good...