It's always a good approach to modding the AI formations.

I have to say, that if you wanna offer this modification to a wider ordiance, you should provide an AI formations balance, that works for every unit scale, and not only for the NORMAL setting. As well, every kind of unit should get a consideration, as well siege and bridge battles.

You can find ie. Darth' Battle AI for M2 as a reference (not only his RTW work), perhaps as a base for your personal adjustments etc.?