Here is a brain dump of some things I may do in 2.42.7 or beyond. Some are simple, well thought out things, others are just pie in the sky may never happen inklings. I'll update the list over time, probalby prioritize it as some point, cross off things that get implemented or voted down, etc.
Please chime in if you have an opinion.
1) Change the Dynamic Costs population target so that it refers only to extant (alive) heterotrophs instead of all bots. The reasons for this are several. First, I think most people running evo sims are primarily interested in evolving heterotrophs, not autotrophs, so setting the target this way would be more intuitive. But more important, counting corpses in the target population causes problems in that it's too easy to end up with a sim full of corpses and no extant organisms where the population is still above the target. At the very least, I think we need to exclude corposes and walls from the target. Autotrophs, I could go either way on.
2) Change No Shot Decay mode so that only energy shots don't decay or perhaps give this as a separate option. The issue is that now that shotvals are MODed, an evo sim full of non decaying shots ends up being really deadly to unevolved bots because a huge percentage of the shots flying around are memory shots or -1 or -6 shots. You end up with a sim full of shots and dead bots.
3) Allow autotrophy to be an evolved trait. Being an autotroph is a way to make a living. It should have advantages (free nrg) and disadvatnages and IMHO organisms should be able to evolve the trait or give it up as selection favors or disfavors it. Perhaps there is a sysvar you have to write to to take advatange of autotrophic energy each cycle but if you do, then a bunch of other sysvars don't work. You can't move under your own power, you can't originate shots or ties, etc. Just the beginnings of an idea...
4) Ties to nowhere. Think of these as quiles or spines for defense. Would need to implement tie/bot collision detection, but one can imagine a bot growing spines to keep preditors at distance...
5) The ability to see shots and shotrefvars. Bots can dodge dangerous shots, seek out -2 shots, smallness has it's advantages, bigness disadvantages, etc.
6) Vector sysvars or somethign like them as described
here.
7) Real shapes and walls with features that use them - mountains, rivers, mazes, capture the flag leagues, rabbit warrens, ant farms, etc. and dynamic features that can change the topology over time.

Jumping. If you need to dodge a shot, esxcape a preditor or leap over a thin wall or stream, a .jump sysvar will take you in the Z direction for some duration as a function of your mass, how much energy you use to jump and the Z axis gravity of the sim.
9) Walls and shapes with Z-Axis height. Ramps. Multi-level sims, accessed via jump or by climbing a ramp. Conversly, burrowing in the field...
10) The option for Brownian motion, fluid viscosity, friction,. etc. to impact shots.
More to come. Saving this for the moment...