This is very interesting news!

I'm wondering. But if I'm a theme developer, and want to compile straight from server, is that going to be possible? in other words, I edit my .sass files, upload them to server, then WordPress will compile my .sass stylesheet and output the necessary .css stylesheet(s) to browser? or do I have still to compile everything locally then upload? I'd prefer the first case, seems more automatic to me... I do it already in less using wp-less, a plugin built on phpless