Having surface stuff optional sonds neat to me. Configuring the damage values of spells should be easy enough (and part of the balancing process anyway), and there alreasy is code for surface versions of the spells. One of the things I always liked about the divinity games were that they had many different and meaningfull difficulty settings, so stuff that switch things up sounds fun to play with.

(as default however Id like the game to be as close to 5e as possible.)