Should I buy an ex- racehorse?

If it hasn't done much racing then it should be a brilliant horse. But i have problems with the horses that have been doing racing since they were born and don't know any different. Because i use horses for campdrafts and sporting so i wear my stirrups longer then jockey's and ive found that the horses dont know the meaning of us kicking them and have really hard mouths because on race horses all you have to do is point them in the right direction, right? thats just my opinion though.