I've suggested this on the other exp-related thread, but I'll repeat it here. Larian should allow players to level past the cap (presumably of 12) by one or both of the following:

1.) multi-classing. The Level 12 cap is class-based, so after reaching 12 in a single class you can always begin taking levels in other classes.
2.) feats. Level "13" fighter would be your level 12 Fighter plus appropriate HP Increase, Applicable Proficiency Bonus Increase, and you get a Feat to compensate for the lack of implemented actual level 13+ Fighter Abilities. Spellcasters would get new spell slots but no higher level spells, along with the stuff mentioned previously.