Since The Great War 100th years anniversary, and after playing quite a lot single and MP battles I think that UG:Gettysburg has the most suitable engine (and everything else too) to cover The Great War battles - campaign. There are not any serious strategy games covering WW1(except maybe for Valiant hearts - not strategy though, and some mods for CoH or TW games which have obviously serious limitations).
I am sure the statement is very premature since UG:Gettysburg is not finished yet but I just thought It would be nice to discuss it a little bit on this forum.
So unleash your ideas