I think that the late Robert Heinlein described Angel perfectly with his definition of the phrase "knight errant." A knight errant is a basically good man on a mission (in Angel's case, of course, that would be his redemption). And as is quite often the case, knights errant spend more than a few nights erring. Angel WANTED to be a hero. He TRIED to be a champion. For the most part, he succeeded. But no one can deny the fact that he slipped on several occasions, whether by honest mistake, out of what he considered justifiable malice, or from just plain stupidity. That doesn't make him any less a good man, it just makes him the poster child for works in progress.
Maybe, if he manages not to get himself dusted by Fray's time, he'll get it right. Hopefully.