because then you'd unlimited instant troops and people could just train enough to put them under the free troop time and rinse repeat until they were out of food/food tokens.
I think improving the curve would work well. If lower research / TH players could make troops slightly faster it would slightly impove the balance. Overdoing it would have a negative effect.
Are you suggesting the barracks effects being reduced and the base speed increased? That does sound like a feasible solution to the end effect I’m suggesting.
Building and upgrading barracks improve troop training speeds along with research under the army strength tree