Good to hear that a ww2 mod will be there either way. I will describe some things to ponder about. Gameplay elements from RO which might be usefull "to have" in ww2-dropteam.
1) multiple players in each tank
Each has it's own role (gunner, driver, mg) which gives great teamplay opportunities.
2) a local voice channel
For tanks this is very essential, only the guyz in your tank can hear this.
3) opening of hatches => multiple view points.
It really gives you a sense of reality to drive a ww2 tank when your body is outside the tophatch. Same goes for the driver, also he can choose to drive with his head sticking out of the tank. Both will be vulnrable to infantry at those moments of course.
4) binoculairs for tankers.
Spotting is very important, might be integrated with calling in artillery on the marked spot.
5) anti-tank obstacles
A limited number to use in the deployment phase. Of course the deformable terrain will do miracles too.
6) destructable models
It's more a "nice-to-have" , but it would be great if buildings could be destructed when taking some HE shells.