New events (especially enemies) are more or less quite tedious to make at least in comparison to the upsides of making them (save the few that have already/recently been made).

Commands to tamper with settings one couldn't affect before would just be pretty much totally useless.

Single player episodes, new tilesets, levels and whatnot are being made consistently and some real great ones have been made very recently.

Pretty much anything else can be done easily (by anyone), but is pointless or worthless.

And whatever handful of things are left would change the entire game to something else and are thus quite out of the question.