Yes my #1 alignment gripe in the BG games was always about Viconia. The kind of "evil" that she was was something that should have allowed for her to be a part of a good-aligned party. But it is extremely difficult, not to mention a management pain in the ass, to try and keep her. The worst part is that by the end of the saga she can have evolved to being a more neutral character, but of course it is too late at that point because you never get to keep her in your party (as a good party) in the first place. So it's a classic catch-22: she needs to evolve to be part of a good party, but she needs to be in your good-aligned party in order to evolve. You can't win either way.