Balance be damned. If one side had a major advantage, let the map show that. End of story.
Balance has its place. Balance by making all vehicles have an exact opposite does NOT but making it so that either side has an equal chance of completing their winning criteria does. There may be a handful of people who are OK with commiting suicide game after game but the more normal/less hardcore realism gamer would much rather maps where balanced. The balance may acheived by spawn point locations, amounts of armer (3 T34s to one tiger etc.) or by making it so that every unit has a counter to every other (by counter I mean something on the map that can kill it, this could take many forms, it could be a tank that was historically very weak vs a specific weapon or AT gun that its enemies have large numbers of, or a plane on a map where there is lots of flak/another good dogfighter, but so long as both sides have an equal opportunity to win the map its good.
Ok in a map where one team has a major advantage, keep that BUT, change their winning conditions so that the other team merely has to stay alive, or something else that does not compare. So for one team they need absolute domination, which because they have a huge numbers advantage IS possible, and the other team merely have too make sure they are not completely overrun.