Back in the sixties in Edinburgh, they had this problem at a folkclub I used to go to. There was one young would-be performer who turned up regularly, played pretty good guitar but couldnt sing to save himself. As he was a quiet, sensitive sort of guy, it wasnt easy to stop him from playing without hurting his feelings. Somehow they managed but still he persevered, improved and became nobody less than the great Bert Jansch!!