I like the idea and my suggestions for simple ways of doing this while retaining some difficulty would be to:

1. Allow all upgrades in the basic style tree to be kept, this would allow a change of focus to explore other styles without much of the early grind.

2. Upon completing the game and restarting the character is reset but gains a trait that increases the effectiveness of all training by 10% and/or a reduction in requiring food/sleep to reduce early game grind, yhe advantage with this method is that several bonus traits could be added allowing a reward for multiple playthroughs.

3. Bought items are kept in the house/fridge.

Thanks for the ideas. We need to think about it!