I have a hunch of why this seasons new twist was put into play.
Remember BB15 and how the twist of that season was to get rid of the floaters. I think the workers at Big Brother have learned from their mistakes (not to say that it was a bad idea, but a twist that know one took advantage of).
Same thing goes with BB13 & 14. In BB13, they thought that bringing in the vets and having the key to be safe was going to impact the game (not so much because of the cast of newbies). Big Brother tries to learn from their mistakes and fix the twist that didn't work from BB13 into BB14 (where coaches were playing).
