Misery difficulty is coming in the very next version.
New features like the robot zoo or the shop sales are out for 1.0, it's time not to be stirring the pot in that way.
Ooh, one quick suggestion if you intend on adding the robot zoo idea later, is to make it be special optional rooms in missions, instead of the "you have to do this every time" that Dredmor generally does. You could make the door look different, too, and have every robot in the room activate upon door opening. And then have a bunch of high-rarity loot boxes in there become accessible if the bots are defeated.
Making it optional specifically would keep it from ever being frustrating.
Overall though I really like that idea.