That is like saying FPSs, RTSs, or 2D-fighting games have been done to death. Turn-based RPG is a very broad category that encompasses all sorts of implementations and game mechanics. Games like Wild ARMS 5 or Breath of Fire: Dragon Quarter play completely different from Dragon Quest, despite being turn based RPGs. New RPGs come out all the time to introduce new and interesting mechanics into the genre. I would say there is still a wealth of untapped potential to be found in turn-based systems.Bullshit.
Turn based has been done to death.