We had a TWH tripper!!! He was a wonderful horse and we tried everything with the farrier. NO help. This horse seemed to just be like a long legged gangley teenager who tripped over their own feet. Even tho this horse was 6 years old and he fell once and tripping badly several times. My hubby was tired of being drawn up in a knot every time he rode him. Especially down a steep hill so we sold him.
I now have a mare who has been wonderful but suddenly started tripping when she was going slightly downhill. We discovered her toes were too short and she did better with a longer toe. She was barefoot all summer and her feet had gotten pretty chipped up. When she was shod it was just too short. She tripped and actually fell with me twice. I was at my wits end. Finally when her toe got longer she was much better. This summer (we ride mostly in the winter) I will have to keep shoes on her.
All horses trip some, especially on a trail ride, they are so busy looking around or being half asleep behind someone else that they trip a little. That type of tripping doesn't bother me but when they start falling or almost going to their knees then it is an issue.
If it was a great horse, have the farrier and vet check them out before you get ride of them.