WotC's Mike Mearls has hinted that we may be able to expect some psionics content soon, possibly in the Unearthed Arcana column. He was asked by Ethan Clow on the Twitterweb "any chance we might see a Psionic class for 5e soon? Perhaps in unearthed arcana?" to which he replied "wouldn't be surprised. I *might* have had a couple prior edition psionics books on my desk last week..." (Thanks to Wolf Hunter for the scoop).