Simple suggestion if at all doable with the Warband engine, make armor/weapon weight have the same effect on cavalry as on infantry. A tincan on an arabian horse with a heavy lance and a polearm is just as maneuverable and fast as someone with no weapons and armor. I know horses are these magical golem creatures in Warband, and violating the basic laws of gravity is but one of their interesting characteristics. Still, this is one area where it should be simple game mechanics and nothing to do with realism.
I've already looked into this idea like 2 years ago. But IIRC I've faced a couple of problems that are not easy to solve. First one is that horses are actually items so you can't really tweak them that good. So I've ended up in several possible ways:
1) Each horse (and loom level) has 3 additional types (separate horses basically who have the same name for player but are different items actually): for light/mid/heavy armoured player (calculations are optional) so each time someone gets on the horse, the item gets updated to an appropriate type. This way requires shitloads of additional items in item list and may cause glitches.
2) Make weight affect riding skill just like wpf. IIRC it's possible to make riding values like 5.75 or 6.40 not just like 5/6/7 etc. This way may cause problems as well as you might be able to spawn on the horse with higher riding requirements because calculations are made after, not before the spawn. Also it would require general lowering of riding requirements.
3) Best way is to ask cmp to make dynamic stats for items but I doubt he would make it.
