An idea...

Go on with what is essentially a clean reset. We will have a new world with all the new biomes, and all the potential that comes with it, and TC will be able to implement some sort of backup scheme to cover our asses if something like this happens again.

Furthermore...

Tuuvi has a point about FTB. Perhaps two worlds, one semi-vanilla as before, and one FTB would work? My dream scenario entails starting with Vanilla, and unlocking access to a separate FTB world for people to go to/stay in if they want. If possible, Orgcraft could have the regular semi-vanilla world, FTB world, the Nether, the End, the unmapped world (whatever it was called), and have it all contained in the discrete live server map.

Thoughts?