Sorry if this post might seem like a necro...
Personally, I'd prefer a completely new title. And since Frictional are preliminarily hinting at two different projects in the site's menu, I wouldn't mind if one of them was something different than a new survival horror game.
I think Frictional are still the best in the business when it comes to this particular, and they've earned it fairly through up to a decade of hard effort and genuine innovation. (Something far too many lesser talents have tried to ape, with usually inferior or slapdash efforts, rare exceptions notwithstanding.) SOMA's refined approach to horror and the depth of the narrative proved to me that Frictional don't need to pigeonhole themselves into a purely survival horror box, they can try creating narrative-and-interaction-heavy-but-in-accord games in other genres as well.
Case in point: I would love to see what a proper, old-school stealth game would turn out like in FG's hands. I wouldn't mind if it was a strictly non-violent stealth game, Frictional's existing horror offerings have already proven they know how to make stealth tense yet functional.
Whichever way things go, I'd like to wish FG lots of good ideas and their creative drive not drying up for whatever titles they're currently putting into pre-production. I've never been worried they wouldn't amaze us with each new title they've developed, and by this point, they've reinforced my trust in them with every single outing. I'm confident they'll bring something new to the table again with the projects they're currently working on. Even if they won't, I think they've done enough work for a lifetime breathing new life into the horror genre.
P.S. Good grief... Have I really been on this forum for over 8,5 years now ? I know I don't visit frequently nowadays, but it's a strange feeling being part of this little community for so long. I still remember FG's humble beginnings, before even Black Plague came out for the first time...
"You... silly Billy !" (Clarence, Penumbra : Black Plague)