Remember it's not all about balance in the sense of statistical tweaking, there are likely going to be a reshuffle of core army units and teching as well which will breathe new life into the game.
This has been done again and again and we end up with a new unit dominating the meta with the old one sent to oblivion.
I would rather thing that need fixing for year like :
XP values
Vet bonuses
Pop
build times
reinforcement times
reinforcement costs
look at and have small changes that bring units/abilities/commander closer to be equally cost efficient so that there more diversity.