I agree that too low of a level cap is very concerning.
A favorite aspect (if not THE favorite) of RPGs for me is the process of advancing my character. A level up is my reward for solving the puzzles of combat, finishing quests, etc. Customizing the path of advancement my character takes is how they become "mine" and a major factor in what draws me into the game.
I experience a substantial drop in my interest in the game once I find out my character is no longer advancing. For example, as soon as I found out that I was at max experience in the early access I stopped playing. I still had tons left to do but I didn't want to do it if there was no possible increase in my character level.
All this is to say, that I'd strongly urge the studio to ensure that character progress can be made continuously throughout the game.
Also... can we maybe get the level 4 cap in the EA removed soon, please? Surely it will help you balance some to let level 5 or 6 characters wrap up Act 1?