if you use WT WW II Tanks in realistic arenas you can do without any premium tanks and do really good, even dominating some maps using correct tactics.
There is a killer catch though,on smaller maps you want your crew not only to be veterans but Ace to reduce the reload time time on target.
Ace normally cost real money, unless you get them from challenges you did, but then again it depends on you playing style and experience with weak-spots on you opponents vehicles, and knowledge of a map.