What might those features be ?
I've enjoyed most aspects of the game.
-edit-
Speculation and ideas. Feel free to ignore:
_Highlighting characters your mouse cursor is over.
_Flexible routing with two-way paths that can be freeling drawn, like a factory game but a lot simpler.
_A new source of food the player can unlock and build ? Fungus perhaps or agriculture with magic ? Those magic wielding goblins could be the ones to make that happen. They only float right now :) .
_Musical jingles for completing goals. There's lots of free music. Let me know if you need something edited(already bought the game, so no payment necessary).
_Bookmarks of locations and shortcuts to recall them for fast navigation
_Waiting area for torture chamber for dropping off and picking up unprocessed slaves. Whips optional.
_Colour highlights of rooms(corner lamp,outline of room or characters...) where a goal has been accomplished, such as "Pregnancy achieved" in breeding rooms. In particular the brothel pillories where slaves can easily die could use a colour outline when the health drops below a certain level. All this before the player gets the automation lanes.
_Commands to send monsters out of growth room. It's not hard, but it's messy. I hope the automation lanes/roads cover this though.