I hate retraining rules - I think they ruin verisimilitude. I think DMs should be able to come up with "under the table" options for modifiying characters to suit unhappy players instead of allowing players to say "I'm tired of my elven fighter - I'm going to become a dragonborn shadow mage."
Retraining doesn't work this way.
And about D&D Next - I'd be happy to see optional retraining of feats/skills/themes as an optional module.