I'm in the middle of refactoring how I handle enemy stats and difficulty levels. In the future the UI will give a lot more free control over how stats grow with floor advancement, and the old difficulty levels will still show up as "presets" to those values.
I'd also like to be able to show some graphs of how player and enemy damage will advance from one floor to the next, to give an idea of how difficult the ROM will be from beginning to end. This will run the generated stats through the game's actual damage formula, and likely also involve an estimation of player level at each floor. I'd probably throw some other factors in like how much armor you plan to buy / will be able to afford.
This will most likely be what v0.80 ends up having. It won't be for a while here, but it should give a lot more configuration freedom and information once it's done.