This is also irritating when I do trading between heroes. When my heroes stack up to trade, the movement drops to the lowest one. Ideal scenario under the current system for a mounted to pass something to a hero on foot is to not move the hero on foot first, ride up the mounted hero by 2 movements, stack up, trade, then break stack.
But sometimes that doesn't happen and I lose one or two movement points just to trade (plus whatever time I lost having one hero run to the other). I always try to keeping stacks of different movement units separated because of this, merging them only when I need the combined firepower. Otherwise, I'm better off using the extra movement to do a few extra tiles of scouting.
