I demand at least 8 players on top of every medium tank (Sherman, Cromwell, Panzer III/IV etc.) as those are the most common ones, 4-5 on light tanks (Stuarts, PzKpfw II...) and again about 6-8 seats on heavy tanks (Tiger, KT, Churchills). Especially now, that 64+ players is real and larger squads are going to be part of it, this would not only add a whole lot of immersion to the mod, but I also sense it would heavily support team/squad work. Think a column of tanks full of infantry on top of those tanks advancing to the front.......
Also proper sitting animations (they already are present on some tanks) would be neat, not just have them crouching there doing 360 turns.