If the person had enough feel and physical skill and let me "ride him by remote control through her," or she had a correction foundation, the horse absolutely would perform the same for both of us.
Oh, but the rider would have to kick his little be-hind into gear more than she thinks she would. This horse was good at cheating and staying behind your leg. That was the one tricky thing about him. He could cruise along and make you think he was using his hind end/giving you all he had to offer. It was usually a lie. The dude was a born slacker, but kind, honest and well-trained.
I think it would be hard for my horse to adjust to someone else, because it took us a long time to adjust to eachother. He is one of those you can't get to worked up. He is a pretty nervous guy, but he is strong and a brave jumper. So you need a soft hand but a firm grip (if that makes any sense at all) and he needs a lighter seat. The technical I think a good rider could do, but he is also a one person horse with trust issues and weird ground habbits.. So that may be hard to overcome.
I would hope any horse I owned would perform as well, or better, for another rider of similar skills. With very few exceptions for extreme personalities, I'd consider it a failing in training if my horse couldn't adjust and work with a new rider
That said, I was the only one who ever rode my mare. It just worked out that way. I wasn't happy with that hole in her experience.
My horse has definite preferences. He likes a quiet, tactful rider. He doesn't mind being asked to work, but he will not tolerate any unfairness. I've seem him launch 2 riders who were too rough with him, and he is not fooling around when he does it. He did it to me once when I threw him badly off balance, and for a quiet little horse, he has a lot of buck. He'll also back up and sit down for anyone too rough with their hands.
My gelding is a tough ride. I'm not saying it is because I am an awesome rider, it is just his buttons are different than any other horse I've ever ridden. So, no he would look way worse. They'd be lucky to get him to canter. Little beast he is.
With my current show horse, yeah, probably they could. Or they could at least get close if they realized that they needed to push hard. He's a great guy, but definitely the most sheer physical work I've ever had to ride in my life. But he isn't complicated and is a good, good soul.
But my half-Arabian? No way, unless they were a pro. He's a good guy, but he's squirrelly. Once you figure him out, he also is not terribly complicated, but if there's a way out of doing something, he'll try it!
I think most competent intermediate riders could could hop on my gelding and handle him fine. My mare, however, tends to act up for riders other than me. It's not like we've got a Black Stallion bonded souls kind of relationship. She's just doesn't like change.
With my fella, I think anyone can get on him and make him look like the good boy he is.
That said, I think different riders will get differing amounts from him. He will truck around, never changing pace, poking his nose with a beginner (as in doesn't know how to post, just bounces to the trot beginner). He will challenge an advanced beginner by throwing a few tricks at them (cutting corners, popping out a shoulder, etc) but will still be safe, steady, and easy to control. If given a rider who has some knowledge, you can get him to rock back, free the shoulder, and really show his training. He would look like the fancy, local level 3' hunter he is.
He certainly wouldn't act like a jerk just to mess with someone, however.
My mare? Absolutely much better. She would end up with a good, competitive amateur or even a pro. She's performing at my level, which is absolutely nowhere near her capability. My poor girl will never reach her potential with me on my best day. The good news? She seems OK with that and even quite happy. I do sometimes think about what she could be doing with another rider. Grand Prix jumpers? Big Eq? Meh. I couldn't part with her.
My four foot jumper mare is also the barn's beginner lesson horse - in fact she is in so much demand by other people that I had to buy a second horse! She can be ridden by anybody. Children can and have galloped her through the forest. She may not perform to the best of her abilities for them, but anybody can ride her (although she likes to get stuck in whoa mode). She performs the best for me - I'm ballsy enough to do the fun stuff, but good enough to stay out of her way, and lazy enough to not demand too much of her.
The other horse? Well, she's a hot mess. She is calm and quiet and very agreeable, but she is... well, she's not the brightest horse I've ever met. You kind of have to micromanage her ever move, or else she will trip over herself. No medical conditions, she's just a ditz. She is SO much fun to ride though.
My mare would now be fine with a different rider from the get go (I've had other people ride her, so I know) as long as said rider is fairly competent and can stay on through, and not be upset by, her "moments"...
Depends on the rider. I definitely know some riders who could hop on my horse and get a worthy performance from him. But... your average middle of the road rider? It wouldn't go well... 17-2, lofty trotting , high headed, go forward, green cantering and needs a rider who will give him confidence? he'd probably scare somebody who was your average rides a few days a week on the flat.
My horse has been exclusively ridden by me with only a handful of exceptions. He goes fine for other professionals, but if an amateur gets on and makes a mistake in a half halt or uses a slightly abrupt leg aid, he has ZERO patience for it. (He lets me know too if he thinks I am riding badly.) if you don't ride the turns with softness but also precision he just says See Ya and starts crow hopping and dropping his shoulder to cut the turn like a cagey old lesson horse.
If he's not lecturing the rider on How The Aids Should Be Applied According To Reggie, he'll have some fun. One student of mine who is a very nice rider with a soft touch he just laid down with at the end of their ride.
He has both an inflated ego and a sense of humor so basically no one else rides him. Lord knows what he'll think up when he realizes someone new has swung a leg over.
Purely hypothetical because I would sleep in a ditch behind a dumpster before I sold my horses but yes he would be perfect for them. If they are a kid or a beginner he would be better than perfect in that he pulls himself up to a walk or a halt if he feels them get unbalanced. Hence the sleeping in the ditch comment!
The response are great, and interesting. My guy is a pleaser, so wants to do good, but it's different for him since it's just been the 2 of us and we know each other onside and out, so when I knew rider gets on him trolley him for the first time, if they rush it he doesn't really respond, he tries hard, but they are not asking the way he's used to and so they are not getting the exact response they want
Now another couple, by the second and third ride, instant response from questions since they are starting to figure it out and riding him how he likes. A soft but supporting ha d with more through your seat then reins method.
Needle to say I have been very proud of him with people trying him, he tries hard, though u can also see he's trying his best to understand what they are asking.
I think even though most things with horses are pretty standard each had a slightly unique technique that works for them and their horse... Like maybe how to get that perfect extended trot b.c you know the right buttons, where person on their first ride might not get it right away..... Unless the horse was a schoolmaster, maybe