Marder III would be a nice edition down the road, in competition style other tanks have some more interest, Su-100, Su-85, Jagdpanzer L/48 and L/70, I vote for a few british cruiser tanks just to get the Panzer III in game.
I still want my Puma scout car, nothing like doing 50+ mph and have a 50mm L/60 on an 8 wheeled vehicle to play with