The pre-merge is just way too long now. It should have dawned on the producers after last season that extending the pre-merge beyond the normal 6 eps was not doing them any favors, and it has been starting to hurt the show in the last few years. Cook Islands was absolutely coma-inducing, and Fiji has been a little better, with a better cast, but the same boredom seems to have set in among fans.
It's obvious the producers like the Pre-merge eps a lot. They have teams, they can shuffle players to throw them off, and there's incentive to keep the stronger players around. The problem is that boot orders are quickly established. Once the first vote happens, there's rarely suspense at TC in subsequent votes. A majority alliance takes hold, and it simply becomes "Which alliance has to go to TC and slaughter a minority tribemember."
This was fine using 16 contestants, as 6 pre-merge eps meant that even if alliances established themselves quickly, in a month the merge would be upon us viewers. (Note that the worst 16-person season, Thailand, extended the pre-merge to 8 eps. Even with the boring pre-merge, we finally see signs of life in the game that die out once the fake merge is revealed.) Also, because of the 8-member starting tribes, players had more incentive to flip votes in order to buy themselves time (Like Marquesas) Now, with 9-10 person starting tribes, if a 5-person alliance takes over, they've got 3-4 easy boots until they have to cannibalize.
One of the obvious fixes is to move the merge # up from 10. 10 worked well with 16 players and a Jury of 7. But with a Jury of 9 and a F3 having become the standard, it really seems like it's time to move the merge up to 11 or 12 players remaining. Doing so also forces the players to form a 6-7 person voting bloc, and history has shown that alliances that large have a tendency to self-destruct and create voting patterns other than pagongings. (See: Pearl Islands, Amazon, Guatemala, Vanuatu, Marquesas.)
In addition, the move to an F3 reduced the number of post-merge eps. It would be a step to balancing the number of pre-finale episodes closer to where it was with 16 contestants. The 9:4 and 8:5 ratios of CI and Fiji are proving to be downright torturous for the viewers at home.
It's a major flaw with the show right now, as much of the tension and fun comes from blindsides and shifting alliances, but with the current setup, we are too often being subjected to players going through the motions.
(I didn't mention 16 players as a solution because it just isn't going to happen. CBS wants to run 13 episodes of the show and a finale, and 18 players allows them to do that with an F3. (20 does it as well, but requires two double boots to keep the # of episodes the same.) Pearl Islands had the outcast TC take up an additional show, while Exile Island spun the F4 off to take up that thirteenth slot.)