Lead Tank.. Not neccesarily heavy
I'm thinking, Tiger, Tiger II, Panthers?, Churchill, 76MM Shermn, Firefly...Basiclly, the 'killers'
With them being SL leader only, you get a spawn point and maybe, possibly, a commander vehicle... I definitely think the commander should be able to lead from the battefield, even if he can't use his assets
I guess the kits aspect is also based on the mentalty that people would take their roles moret seriously if they selected it as a kit from the menu... And uniforms to go with it
Frankly, I put more heart and mind into te 'tread' aspect of the suggestion