Not keen on it. I don't agree that it's 'softer' than
Rowena (though I totally agree about the unattractive weeniness of
Rowena), and I don't think tacking an 'a' on an already feminine or unisex name makes it more feminine. I like
Rowan on a girl though, prefer it actually. I like
Rohan for a boy
I do like
Morwenna. If you don't dislike place names, what about
Ravenna?
http://www.behindthename.com/pnl/167578