retiring sensitive show horse

Question
I know it's a holiday weekend but I would certainly appreciate any response you could give as soon as possible.
I have a 13 year old Periaptor son who has an excellent show record in five gaited.
A few years ago (with a previous owner) he started refusing the gate and spooking at everything in the show ring.  He went to two more show homes with the same result before I finally bought him to retire him.

I planned to paddock board him, outdoors 24/7 with a partner, a shed, a blanket, and good grain and hay. (He's been a complete stall baby all his life)  I've had him for 10 months and the barn owner turns him out during the day and on an occasional night but has come to the conclusion that he will never make it living outdoors 24/7.  He does get welts from mosquitoe bites and she says he is most content when in his stall. She thinks he will be too nervous outside and needs to be in a stall in rain or wind, etc.  The problem is he is afraid of everything outside of  his stall to the point where I can't even ride him in the outdoor arena without him freaking out.  He either freezes up or gives an extreme overreaction to as little as a shadow.
I feel living outdoors would help desensitize him.  The barn owner now has a trainer wanting to buy him and thinks a show barn will be better for him, that he will be more in his element, stalled and pampered.  This trainer (buyer)is going to give us an  answer this Tuesday.

Is it true that a very sensitive "stall baby" can never adjust to outdoor living?  Also is it possible to get a horse to stop over-reacting to everything to the point where  I may someday be able to ride him down the road and not get killed?  At  this point I feel like my trainer/barn owner has set up a sale that might break my heart because she feels he will never be the horse I need him to be ( a horse I can hack around outside on).  I'm on the fence as to whether to let this sale go through (the buyer's a great trainer) or if I might salvage this horse that WAS my dream.  I think I may have given my trainer too much power and I'm not ready to give up on this horse.  I've seen nervous horses completely turn around when turned out 24/7 but she refuses to do this with him.  Perhaps she knows something I don't.

What do you think?

Answer
Is there a possibility this horse has something going wrong with one or both of his eyes that would cause some of this?  He may be seeing "shadows" instead of accurately seeing what is out there, only a vet could tell this, of course.

And there is also possibility that he has been burned out on showing, and has developed these behaviors in protest.

While there are some horses that will always feel safer, or prefer a stall?  Most do fine outdoors, and that goes for even the very "hot" breeds too.  

I grew up with Saddlebreds, and also have worked with Thoroughbreds, and those came off the track for the most part and were turned out in pastures 24/7 after they became broodmares, and they did just fine.

It could be, with the less training that his feed is now too hot.  He may do better on grass hay, if he is getting alfalfa, or oats?  Changing some of his feed will not cost much, and you will be able to see a difference fairly quickly, if you can get them to feed what you want at the barn.

He also might benefit from a CBC, which again a vet will have to do, to see where his hormones are at.  He maybe could benefit from some type of calming med, or supplement.  A complete review of his feed, and hay analysis by your vet would go a long way to seeing if this horse needs "calmer feed", and again, it is something I have seen work wonders, just a feed or hay change.

I really think the eye thing is something to look into.  The fact that it happened fairly quickly could just mean, (in the ring) that the condition worsened to the point "monsters" were present.  Eyes are funny things. Great when they work right, but not so hot when something goes wrong.

And if this is your horse?  Then your wishes need to be followed.  If she is bucking you this strongly on this, is there a chance the "buyer" is an associate of hers and they are wanting to buy cheap, and sell big, with her getting a split of the money?  I would be very suspicious of this if I were you.  

But be aware that if you don't do as she wishes, that if she is behind some of the problems, they will get worse, as in horse being fed wrong, not being turned out, or maybe tormented to make it worse.  

Personally, I would consider changing barns.  If you as a customer/boarder cannot be satisfied that your wishes for YOUR horse are followed?  Then you are at the wrong barn.

I don't think that the horse is being given the chance to see how he will do, based on what you have written, and my first thought about eyes getting checked, with CBC done, and vet doing hay analysis, and checking into feed issues also, stands.

Let me know how this is going, and whether you have seen any improvement, or what vet said.

I would not sell him as I don't think trainer has your best interests at heart here.