The problem with Allied TDs is not their max range but their performance at max range.
The can have little reason to close to any target since they can snipe them from max range and damage them (hit and penetrate) with very high probability.
The combination of high base stat and high vet bonuses is simply too much.
The guns of this unis could easily get a different profile lowering things like ROF, accuracy, Penetration at max range so that they become less effective at those ranges.
