another person putting their hand up hoping for the game to get closer to the 5e rules, its a good ruleset, there really is zero need to change any of the core mechanics, sure by all means add some others and perhaps have options to turn on house rules. But wherever possible, please stick to 5e rules.
Surfaces are good as an addition to the game, but they should work on saving throws for entering and each round you're in it. Fewer things should create them too.
bonus actions for certain things might be nice to have be something you can toggle (bonus action healing potions ala Critical Role for example), but using items should be a standard action by default, as should disengaging etc.
