The limit to just horses is just sticking within the IP. All they had in Tolkien's tales were horses. They did work in allowing Dwarves to ride 'em...then again, all hobbits swim too. While there's limited changes to IPs for every game that uses one, it's generally extremely limited, since the IP controls the content.
Horse naming would be cool. Not to hard, just another piece to add to the database.
Horse Animations, possible, but I wouldn't be betting on it. Main reason is boning the models and working out the animations. Usually when you are mounted your character becomes a fixture to the mount. In LOTRO it looks like it's at the ankle/shin area, so they can get the body movement and bounce going as you ride. To add in animations for this is different then just for the characters themselves, since then you have to add in all the points of contact so it remains one model. This being the main reason we don't see much in the way of mounted combat in MMOs.
Horse Autorun, I would also doubt we'll see. Simply because mob attacks can dismount you. The horse AI will use the fastest path to the target stable, and would follow the same pathing routes they have laid in for mobs. So it could run into mobs as easy as heading straight into a lake and dismounting you. Most MMOs feel this is a working as intended to have you drive the horse, the perk comes from you can choose a faster route by going overland and not following an intended path. If you want to be AFK for the ride, you pay the price at the stable. It's commonplace in MMOs.
Horse walking animation fix would be something that would most likely come about if talked about enough. High on the list, probably not. Even though it seems a simple fix, it's a few hours pay to an animator...which can be pretty pricey. If enough said it was taking from the imersion in the game, I'm sure they'd pay the price to make folks happy.
Mount armor and various mounts I can assure will not be in unless they address the issue of mounts for MPs in the same fashion. As it stands now, player on a mount already has a armor bonus coming in and even if the MP takes it down, they have wasted power to fight a FREEP at full power. Plus a player can make distance and pop their mount to escape. So, basically, after the code in MP mounts, then they could look into this. Will they, I don't know. Could be the IP told them no MP mounts since Wargs are playable.
Oh and you can hotkey your mount, no need for slots

Plus you can hotkey your instruments, as well as all the other slotable items to change them on the fly. I use this with those items as well as weapons, armor, and items so I can change my stats on the fly dependant on situation. They have 5 UI quickbars built in. "Ctrl + \" will open the window to place them, you turn them on in the options.
So basically it all boils down to balance issues and costs. Mostly I would imagine costs, since addressing issues of balance means spending money. Then it's the whole return on investment. Would these changes bring in more profit.
And this is only tip of the iceburg, since you also have processing footprint and lag. More skins varients to load means more work on the processor, and armor on the horses and varied horses and armor means more poly count, which equals less framerate.
Good concepts, good ideas all of them. But in the math of the MMO business world, I dunno. Who know's what the future holds.
