As for redeeming the evil companions, I do not think that it's a bad thing, if it's written well and if it's done in a logical way. Alignment can change and it's way more likely for someone to change from let's say evil -> neutral, than from evil -> good. Certainly, a reverse process (becoming corrupted) could happen for Gale or Shadowheart...
Yes it's fine when you do it with one of your companions. But when you do this with EVERY one of your companions, it becomes a ridiculous and pathetic gimmick.
