Do you lose anything by not getting to level 12?
In general?
One ASI, or Feat choice ...
Impact of such consequence varies, depending on your class.
BUT!!!
We have seen Larian is implementing some stuff (mainly spells) that seems suspiciously simmilar to things that were meaned for even higher levels.
So there is certain risk (or possibility, depending on your opinion) that there will be some special bonus feature for people who will get all 12 levels in single class.
Kinda funny we never find out until it will be too late, since there is no class prewiev implemented. xD
