Here are my suggestions:
- Start out with the horse from Oblivion. With this horse, we can a) interact with people and objects,
get first-person view back, c) use it as a pack horse, d) upgrade it with various magical stones stored within the saddlebags, e) have more than one speed (walk, trot, run, etc.). (Optional: use the model of the Skyrim horse, animations and all.)
- Offer two (or more) types of horses. I thought this could be incredible self-evident, but a) regular old rider;
trained warhorse who has a range of abilities and commands, including fighting whilst you ride it. All types of horses should be able to follow simple commands, like "wait here til I come back"!
- Implement combat on horseback. How hard can it be? Ask Mount and Blade how they did it. It's good.
- Would someone give my housecarl a horse please? Give companions a horse for the sake of Talos. What would people think of me if I ride a horse and make my servant belabor the wilds of Skyrim on foot? Besides, if my housecarl can keep up with my horse, it makes me look bad. Why do I need a horse, then?
- Craftable horse armor. This is really a secondary thing. Most people don't want their horse to fight I guess.
- Horses are expensive for what little they offer and how easily they die. I think it is hilarious to watch my horse fly tens of feet into the air when a giant stomps it, but my mirth is soon destroyed as I realize that is 1000 septims floating above the giant's lofty melon. I would say add most of these improvements (1-2 at least) and then the gold will be worth spending.