Where I think the really interesting parts missing are those in real neural circuits do, especially since the connections are more heterogenous, and the dynamics are much more fluid and time-dependent, whereas typical at-scale computer neurons obviously operate at fixed time steps, and don't exactly have bursters etc.
I wrote a very large scale distributed simulations for real neurons (straight from imaging datasets) when I was working in a TMS lab, and a longtime side project I always wanted to get going was some kind of pipeline for spitting out neuromechanical/cable-theoretic RTL tailored to specific morphologies and networking them according to their connectomes. I don't even think I would see any performance improvements, it just feels fun.