leagris: Oh, look, I had this problem. Then I've stopped using lead, because slime balls are valuable and rare for me and I was getting tired of leads just…vanishing. So I've implemented program of highway stations. Just ride in, dismount, go do whatever you need. Horse will be there.
This issue doesn't seem to affect if animal is hanging from a lead. I've hung up all 5 kinds of farm animals from roof of my animal farm (yeah, I'm cruel to them. I enjoy that), and just…left them there. They jump in mid air, held by the lead, and are like this for…well, months. More than half year. IRL. God knows how many in game days. Lead is always there. Never broke.
How ever, I have different issue. I dismout horse and he just…dissapears. He is rendered where I've mounted him, but actualy where I dismounted. Unloading and then loading the chunk he is in, helps.
To the topic: Yeah, sure, whatever will make horse faster.
I like the lightweight but not the others. Regeneration can be applied with a potion and haybales can be used to increase health. The effects of calvery and rampage should be built into the horses as they make logical sense. Horse armor should be able to receive the same enchants as regular armor.
I would also assume that saddles and horse armor will have durbaility in addition to enchants.