Surely duplicates, but I'll list just in case anything's not covered:
- Button to turn off rendering and simulate at max speed?
- Optionally mutate joints (positions & weights), bones (weight), muscles (strength & extendability). I get this isn't trivial, but would be cool. Maybe have the mutations stored along with the neural net, so the the actual creature's physical structure = designed structure + evolved deltas. (Sorry if I'm making bad guesses about how your code works :))
- Would be nice if you could zoom out more or make grid smaller.
- Selection masking by type (select multiple muscles or multiple bones) + if multiple things of same type are selected, allow editing a property of all selected objects.
- Copy/paste selected objects. E.g. one could design a 4-bone leg and then replicate it.
Really, the first two would be enough to make a huge improvement, I think.