It's safe to say that Wallis Simpson ruined this name, considering her reputation during her lifetime and the fact that the rest of the British Royal Family hated her. I wouldn't recommend it. It would sound horrible on a girl regardless.
I'm beginning to like this name. I think that the replacement of the "ace" at the end with an "is" definitely makes the name look more feminine. Some decent nicknames for this name could be Liz or Lisa.