Gender divide from the moment they enter, or perhaps Day 2 - make it a social experiment again. Neither male or female group is better off than the other aka rich/poor divide. It's just simply how will they react with a plastic wall seperating men from women? Only time they can share a room before the divide ends is in a reward room similar to BB4
Lucky number 7 - BB calls 1 HM to the DR, whoever enters is simply told to rejoin the group, 2nd person called also to rejoin the group, 3rd, 4th, 5th and 6th all the same but the lucky 7th person is told they are immune from the first eviction and whichever 2 HMs they nominate will automatically face eviction with whoever the rest of the house decide. They will be pampered for the entire first week before automatically facing eviction themself in week 2
House in lockdown - HMs are told they have 5 minutes to grab any clothes or toiletries and make their way to the garden. Once they are in the garden the shutters will close and the HMs have to live in the garden for the first few days with only the DR and 1 or 2 toilets as rooms. They must sleep in hammocks and use an outdoor shower. The garden would be huge and interesting so not to bore the viewers. Maybe have a few sculptures, the pool, several plants, water feature, exotic pet (chameleon?), a few fish, return of the chickens, a den/nest/loft/snug, outdoor seating area, a picnic table, a Tree of Temptation/Bob Righter/Davina McCaw similar item
Return of the live tasks - but bigger and better with the prize money at stake! - Now on launch night and eviction nights rather than Saturdays so it'll draw in more viewers and already have a crowd round the house.
Powercut - sveral hours after the HMs enter, during the middle of a big party BB should stage a powercut and only use the cameras from the camera runs to imply the ones fixed in the house are also not responsive. After several minutes (and in the event of anoyone panicking) some of the production team will escort HMs to the task room, supply them with torches and the food from the party and install few nightlights to a toilet for HMs to access. This would be the only time anyone other than HMs enter the house. Think of the BB4 bomb scare/BB5 fight night - social experiemtn side of things again
Oh, and first HM to go to bed is a rotten egg! - BB encourages the HMs to stay awake until after 4am. Any HMs that attempt to sleep before the designated time has rotten eggs thrown at them from shoots in the ceiling!