A 1/72 artillery crew for WW2 would, I think, be very successful. And, perhaps some of the more common field guns used by the Allies (the German ones have all been done, and in droves). The same treatment for WW2 as HaT have done for WW1.

That's not to say that I think WW1 is done with - I'd like to see all sorts of things for WW1 - but I won't thread hijack!