If the current Post-RotJ is any indication, any and all reincarnations of the Sith will only be broken fragmented shadows of the real Sith line that ended with Reborn Palpatine, not for a very long time will we see Sith even a percentage the strength of the Banite line.
Oh and for anyone who says 'Caedus' he was the last hope for the Order of the Sith Lords as a proper force, unfortunately for the Sith, Lumiya and Vergere didn't remove his love for his family, much the same failure as suffered by Sidious, as Sidious was 'killed' by a redeemed Anakin, Caedus was figuratively killed by Jacen's love for his own family.
The Sith are basically finished, a few organizations will pop up here and there, but nothing of true significance and sustainability.
Will this change for the Sequels? I am going to guess not, especially if Lucas has anything to say about it.
Probably, especially since he stated thats when the Sith line ended at the death of Palps. I could however see a sort of fake "sith" cult or something of the sort.