[user104658]

I honestly think the thing that would solve most of the problems is having no head-to-heads. Minimum 3 (or even 4) in every vote makes vote manipulation much harder, twists or no twists.

Also vote to save over vote to evict. Frustrating as it can be ... it ultimately always makes for a more entertaining show, and culls some of the boring characters earlier. You need a good "mix" with some slightly bland ones still in there or it all gets a bit much, BUT if they keep nominations simple (not so many twists, not putting people up for failing a task or crap like that) you'll inevitably have a few "nicey nicey" characters who dodge nomination right until the end.