Here's my idea. Doesn't necessarily mess with old players, but could be a good twist:

Two tribe season. Exile island. At the end of each reward, the winning team picks a tribe member from the losing team. At the SAME time, the losing team picks a tribe member from the winning team. Ensuring both selections are without the context of who from your team is going.

AT EXILE: Before the two castaways are allowed to talk to each other they come to a covered table (with a note) and are instructed to stand on opposite sides and open the note. The note says to uncover the table. On the table is a hidden immunity idol(!) split into two symmetrical parts (they could lock together or something). Additionally, there are four closed boxes on the table (two on each side).

Inside one box the word STEAL is inscribed. Inside the other is the word SHARE. Both are instructed to pick one of the two. Before picking they have the opportunity to speak to each other for the first time. (Production may have to encourage this dialogue)

•If both survivors pick share, they each get half of an idol.

•If both survivors pick steal, they each get nothing.

•If one survivor picks steal while the other picks share. The one who picked steal gets a full idol.

Once both players have talked it out and discussed, they reveal at the same time. Idol parts are distributed.

Fast forward to when they return to their tribes…

Jeff gives both castaways an opportunity to speak. E.g "how was it out there?" This is critical. Based on if one got burned, or if they cooperated drama could unfold. "That jerk has an idol." Lots of opportunities for double crossing others early AND building cross-tribe relations early into the game (which potentially makes for a less predictable post-merge, which Jeff mentioned is the dilemma of a two-tribe season.)

It encourages decision making that pits your want to have a full idol against burning another player. Short term pains for long term gains or vice versa.

The major concern is this has the potential to put too many idols into the game. Possible fixes include idols that expire at the merge, hiding the idol pieces (instead of two idol pieces on the table, two bundles, which may or may not have idol pieces), or something else.