I can wait for the update. Thats not the problem.
1. I cant play 1.5 or 1.4.7 now because I know I wont be able to keep my progress.
2. Every time they have an update all worlds get completely broken.
Yes, you can play 1.5 or 1.4.7 now and play them until you're ready to reset the world and then update to the latest pack at that time.
As far as worlds getting broken, that's unavoidable when you're trying to mod something as heavily as the FTB packs do. MC changes, Forge changes, mods change. It's going to happen.