I would really love to see this for 2.0, they have already talked about adding in some iOS and android apps for XIV. No real idea what those will do yet, but still.

A OSX Client wouldn't be too hard to pull off, after all there are tools that help the transition over, and while it's not the biggest market share, it's still a market share. I for one use both, and would love to have a XIV client running on OSX. I don't think they should do that now, but with the 2.0 client, it could be the perfect time.