Just a fun little idea I had. Wouldn't be the default, but might be fun to play with:
With bots as capsule shapes, you can think of them as boats with a bow and an aft, etc. Which got me thinking about how exactly a bot is able to mover around. I've always imagined it's with little retrorockets, or maybe cillia. But maybe they use sails. Maybe you can set a wind in the sim to blow in a certain direction, and the bots have to learn to maneuver with their rudder and sail to get around. They could change the angle of their sail to best catch the wind and use their rudder to navigate and turn.
From a biological standpoints it's pretty silly of course. But I bet the bots would be the first AI used to steer a wind powered vessel
