I dunno.....still leary (though I could be wrong)....
The intensity which Jane killed Thomas leads me to believe the Sherrif is "dead", so I can't imagain Thomas reviving himself at a later date. However, I could see the writers faking us out, even in print, reviving the "real" Red John in the future......
But if Thomas is truly Red John.....it will be interesting to see how the series continues.....what other problem will Jane face to propel the series. A new villian.