His proportions just aren't all that great to use him as a breeding horse. I don't want to go into detail tearing your horse down to explain exactly, but there is no reason to keep this disproportionate horse who might have a great future as a riding horse a stallion when there are many BEAUTIFUL, confirmationally correct horses out there at stud. He is very cute, but cute does not
mean breeding material.
Edit: Okay, I looked at the pictures some more... and I can't help it. I want to say, first... other than seeing he looks disproportionate, the pictures aren't great to assessing exact confirmation. He does, however, look a bit over in the knees and cow-hocked. Perhaps it is the angles, but both depict this :( I reitterate, very cute, though!