They already have options for choosing your own end of the federation, the genesis wave, an invasion of 7000 borg ships, the super plagues, majority of the fleet wiped out by the Totality, etc. The details differ, but they're all the same in killing a few trillion here or there, rendering large portions of the Federation and allies lifeless and without resources, and providing a last minute magic solution so the series can continued.
To bathe a cat takes brute force, perseverance, courage of conviction - and a cat.
The last ingredient is usually hardest to come by.
- Stephen Baker