Vote to save will indeed keep her there for a while, though I fear she might become as hated as Tully.
If we revert back to a pool of 3 nominees each week, then I fear a Tully type situation where the public actually cottoned on to the fact that saving the sugar sisters was essentially a vote to evict Tully. The general public are slowly but surely wising up to how the vote to save actually works, so if Priya becomes a real love/hate figure, it might be harder for us to keep her in.
I'm hoping Alex sticks with the 6 nominees format again this year - it really helped somebody like Tim to play the game as well as he did, where giving a vanilla character like Caleb 4 points pretty much guaranteed they'd be up. I imagine we will see 6 (or maybe just 4) nominees minimum, as couples will be nominated together, and so it's likely they'll have the red zone as the 3 most nominated couples. In a situation like that, Priya should be safe.