I try to keep my options open in case a really strong class comes along that I feel will stay strong, IF I'm playing a class I feel will stay weak, yes. Especially for healing. If I roll the worst healer, and I have a max level of the best healer, and it isn't too much trouble swapping at that time in the game, I will swap.
Will I swap my entire character for a 3% dps increase? Probably not, but it would bother me to be honest.