Something on my list is to add (obviously optional) switches to turn various single bot capabilites off. For example, I have been considerring an option that would turn off the movement sysvars. This would mean that bots would have to evolve their own mechanisms for locomotion based on the physics of the system, which would select heavily for multbots. For example, using ties for swimming or tie torque/tie length and fixing and unfixing to walk.
I could do the same thing for vision if people really wanted I.e. turn off all eyes but .eye5 or turn off the distance values so all you know is that there is something in the eye's field of view, but not how far....
Personally, I can think of many things that would favor the evolution of multibots but I think it may require some tweaks to costs and also increased topological complexity before they really take off. As to the former, I see cell specialization as a key driver for MB's. I.e. some cells get good at attacking, others good at storing nrg, others good at defense, etc. I'm wondering whether we need to tweak costs or add additional ones that favor this I.e. that make it more costly for a single cell to do multiple things that it is for two separate cells to specialize.
As to the latter, I can envision MB's being necessary to climb over obstacles, bridge chasms, fly, swim, move faster, dig deeper and perhaps more importantly, think better. A long distance goal of mine is to create morphological artifacts (think nurons) which favor MB's hooking up to be able to think better. It's not a complete idea yet, but something I would like to explore down the road.