Game's brilliant, but why can't we start NG after beating the game?

The game only allows for NG+, meaning you carry over your level and most of your gear. While the gear I can choose not to use, the level will make us faceroll the content. Doesn't make a lot of sense tbh.

I guess we can delete game data to get a clean start but sounds like a very weird design choice.

EDIT: Yeah... Not the best experience. Keeping the level makes you way too overpowered in NG+. Decided to delete my save data to start from scratch :S