Horses for squishy heroes like mages also make sense. Karl Franz on Deathclaw is an exception - the mobility is just awesome. But I don't have time to micro in that way, so generally make my characters walk. Makes sense to me, given the way charge bonuses work. In terms of mounts, someone said that re-charging, a mounted Lord will beat a non-mounted one. Without such talents, my Empire captains generally are (slightly) outfought by AI heroes.ĮDIT: Just checked in game and it's 15% HP and 15% weapon strength, not 30%. With those talents, my Karl Franz could whip Archaon. However, 30% more health seems a big chunk and 30% more damage seems a big chunk to be taking out of health, so I went for those two. It seemed to me looking at the numbers that lots of the stat boosts (to attack, defence, armor and charge) were small relative to the total - a few points.
It's a good question and I confess my knowledge about the maths behind TWW combat is sufficiently murky that I can't give a definitive answer.