In most episodes, the identity of the killer is kept a secret until Jane set them up. And giving the identity of Red John on a list is not in their nature. I believed that the list contains some friends of Red John but not the man himself. Otherwise it would very anticlimatic because we know it would be one of the seven.

This is just an observation. There have only two other serial killers on the show. The one that RJ killed and the one in the second episode of the season 1. The sheriff appeared in the latter. It could be a coincidence. But he could be RJ or his friend.