Wouldn't be better a new complete rewritten engine?

[XTF]

If that engine progresses into something promising, we'll certainly try to support it, but as said before: Multiple people and teams have started engines before, and, as far as I know, none of them was ever completed.
So it'll take more than rendered tiles to grab my attention.

Stumbled across http://open-ra.org/ some time ago. Looks like a decent project.