Most of these gimmick twists are put on by CBS, not the producers. Phil and Bertram and Elise all prefer traditional seasons. But CBS said the show needed to evolve to survive (direct quote from an interview with Tassler, though I can't remember the news source). And now with Tassler gone, the new CBS chief of programming doesn't appear to care for the show. In his intro interview when asked about the networks reality shows, he only mentioned Survivor and BB.
So basically, CBS mandated changes due to the ratings which were lagging. And instead of adding new viewers with these 'great ideas', they are just alienating more and more of the core audience.
The show did ok for itself on Friday nights, though at this stage of the show's life, you can't fault CBS too much for pushing it to summer and trying something new like Hunted.