Uh? Look at your argument, it should be clear why there's a double standard.
Males character are power fantasies, sure, but for whom? Male gamers.
Female characters are sexual fantasies, again, for male gamers, precisely the bi/straight kind.
Dungeon Siege III doesn't do AS bad as other games on that regard (most of the Lescanzi witches and Anjali are pretty sensible.. Leona and Katarina aren't), but it does pretty badly compared to Obsidian's games.