I noticed that walking and running only ever look 'right' when you're a default height.
If you're small, the ground sweeps below you.
If you're big, you walk faster than the ground goes.
In an experimental game I had been working on, the animation played, and the rate that it played at was according to both your characters scale, andcurrent speed.
A small character would have to gallop or run to reach the speed of larger characters just walking.