I pretty much agree with what you're saying here. (You can pick yourself up off the floor now.) Angel is following the prophecy while Buffy is thinking of how to defy it; and the prophecy has backfired on him.

It seems clear he didn't realise that fulfilling the prophecy would lead to mass slaughter and destruction - or maybe he thought it would be less bad than the alternative, whatever that was. We may know more when the final arc is published. I still disagree that the deaths were part of his plan, though it may be a case of "If he can do it without any Slayers at all dying, that's best, but if some have to die, that's not as bad as not trying at all." It's a war, and not a war Angel started, and people die in wars.

That doesn't make him "good", it makes him a screw-up who did harm with good intentions. Like almost all the other 'Buffy' characters.