I respect that the Wesnoth community may not want to go this route, and wouldn't blame anyone for that at all. My suggestion was more along the lines of "here's an option which won't be nearly as painful" than anything else.

While Unity3D is conditionally free-as-in-beer, it definitely isn't free-as-in-speech. Unreal Engine has recently gone kinda free too, but not really.

In any event, best wishes to the Wesnoth community and continued fun to be had by both those playing it and those progressing it.