The game is heavily and as closely as Larian feel they can make it, to D&D 5th. Which has caps and limits by design.
They are telling the story of a single [ Large ] Campaign. Typically Campaigns are split up into level brackets and this one goes through them like candy.
If you're looking for level breaking games and the like, you're likely going to be waiting for when the Workshop is added and the modders start going full ham on the finished product.
The way the game is designed from the ground up? Would not support a cap-less system. You would quickly curbstomp what Larian has in play.
