Improved Programmable Block gameplay limits.
Being a .NET Developer by trade, the inclusion of C# Programmable Blocks in SE was one of my biggest draws to the game.
It makes me sad that they were moved to Experimental Mode, but given their scope for abuse/misuse it was a completely understandable decision.
Personally I'd like to see more strict rules on the execution of Programmable Blocks in general, to reduce their potential to cause performance issues and bring them back from Experimental Mode.
Setting strict execution resource per game tick limits would allow slower scripts (which can be useful) to still be used, but require they only run every 100 ticks.
Small, efficiently designed scripts could continue to run on the 1/10 tick cycles without issue.
If a script breaks the resource/tick limit (or the existing hard limits, which could also be tightened) it can be made to fail as it would now.
For multiplayer environments, the idea of PCUs could be applied to PB execution resources per tick. This would prevent players/factions from abusing the placement of multiple PBs to cause performance issues.
A final, potentially interesting, mechanic would be to tie Programmable Block power consumption to how much physical execution resources it requires, dynamically draining power depending on how the execution flow played out in the last calculation cycle.
This means that slower scripts could punish the user with huge power spikes before failing, while rewarding the creation of efficient scripts with better results/MWh consumed.