It has great support for js, node, go, .net etc. already. We'll hopefully add Python & R support soon.
I've heard a great number of rumors regarding bringing Visual Studio (full) to Mac OS X and Linux. Many from Microsoft folks. Not saying they have to be true but I should be shocked if it wasn't at least being researched and looked at.
Personally speaking I would love for that to happen. There is room for both an XL IDE and a XS IDE imho.