this game (while i havent played the recent version yet, i have downloaded it) got me thinking, and after reading some other comments, a very good example of a rougelike came to mind. an old one called Castle of the winds. it would be an amazing reference material for a game of this design and may even give you a few ideas.

I played a bit of Castle of the Winds back in the day, but for some reason struggled to really "get" it. I'll have to give it another shot, as it seems pretty similar to Larn (but with a larger magic focus)