The biggest problem that they will never be able to get away from is that people just know how to play the game too much now. In the first couple of years, the contestants were a social experiment. From about the third series onwards, producers obviously noted that people were starting to work out how to play the game more so started influencing the direction of the show (e.g. evil Big Brother etc) to make it more unpredictable. The problem is that the contestants are now savvy to these tricks as well - they know it's highly likely they'll be unexpected evictions, a secret room, fake evictions, secret tasks etc. They also know what to do to get screen time in the daily edit and to win people over. The public have latched on this as well - it's a bit like the X Factor syndrome where people have stopped watching because they know the sob stories / fake running off to grab a contestant to change their mind etc - it's all been done too many times before so people turn off. Going back to basics won't stop the underlying problem that most contestants know how to work the game to their advantage which leads to a predictable show.
I do wonder whether a twist on it would be to put people in that work as teams which they stay in throughout the run, rather than individuals and place them in two/three mini houses that also share a central complex. A Big Brother village perhaps? Possibly even take away the power from the house to nominate and that everyone or teams are up for eviction every week. Could change the dynamic a bit more possibly.
I personally think the Emma and Rylan dynamic works well for the show because they treat it like Davina did - with a bit of fun but also a true love for the show they're presenting. I'd rather they didn't go - I couldn't bear another show possibly being presented by Stephen Mulhern or Ore Oduba!