my feature requests in no particular order:
change the way the new "custom modifiers only on certain floors" feature is implemented. right now i have to make a custom modifier for each floor, and choose which floor it applies to. if instead i could make one modifier, and then choose which floor it applies to in the map editor instead of modifier editor. a similar feature to declare in the map what floor an entity, key, hp, etc is for would be cool too. i realize it's an inherently a "one-floor wolf3d with other floors added later" engine but that doesn't mean it has to stay that way forever.
add support for 2 skies, one cylinder and one plane and/or ability to choose between spherical projection or cylindrical projection for skies. and/or doublesky like in hexen
four or eight directions for enemies and decorations.
option to include more animation frames for weapons, enemies, etc. for smoother animation possibilities
support lightwave-format .obj files in addition to quake md3.
i know some of these are probably big asks, and many would be impossible to do as engine is now cuz they seem to be hardcoded. in general i would like to see more doom, less wolfenstein.