I wanted to get some input on this idea. Horses tend to be extremely slow on raising up their stats for their combat maneuvers. For Dodge's case, non-existent. Horses also have a habit of vanishing off into the code sometimes, meaning a person has to start over working on their skills.
So, rather than spending 5 years working on their ability to kick, and 15 for dodging, why not have riding from the mounted player contribute to a majority of their rolls? it'd make a mounted horse more adept in surviving in combat if they get locked onto, as some mobiles (and characters) do aim abilities at the warhorses. It'd also cut down a lot of the work in raising a new horse depending on the style of bonus for the horse.
one approach would be going for a 1 to 1 exchange with riding onto a Warhorse's ability to kick and bite people. Mount on your newly obtained companion, and he is capable of punting squirrels into lower orbit. or wiffing every hit due to only having 150 riding.
A second alternative is having only a portion of riding apply to the mount, while still allowing horses to benefit from training over time and horse merchant events.
Either way, if it was possible to train up a horse's combat capabilities easier, it also can lead into the purpose of this: To nerf trample and tie it to the horse's combat rolls rather than the riding skill. Rather than the current check, a player would roll a regular dodge roll to a melee strike, rather than the weird calculation that has riding rolling over 5500. As well with better rolls, we can start putting forward more suggestions for warhorse combat maneuvers, especially of those that are meant to dismount opponents using a horse's own attack roll.
#1: The fact that mounts gain skill is a bug. I believe it was once addressed but from the sound of things, it was not fully fixed. It is not one of those bugs that will cause you to be banned from the game. However, if you happen to gain from it, one day you may find that your horse has been reset and all that effort has gone to waste when the 'bug' is fixed.
#2: Your riding skill does indeed affect various different combat aspects of your mount. Such as how well you can control them from fleeing if they are not wartrained or the effectiveness versus many opponents or how well you can trample or many other little things that take your riding skill into account.
Raising all horse stats in general only serves things like CVC which is not in my opinion a large focus of the MUD and will only result in them being overpowered for everyday use, making them even more a necessary purchase since then their utility will be too great to ignore for everyone, not just combat characters.