You know, when I started this project I was faced with a choice. Do I use the current Entity system, with its built-in serialization, networking and all that other stuff it does automatically.. or do I implement our own system.
At that time the idea of implementing our own gameloop seemed daunting. All the scene , physics, input, network management. Combine that with the fact that we wanted it to be a comfortable transition for people to come from Garry's Mod, it seemed like a no brainer.
But as time has gone on, we've taken control of all those things on the c# side. We can create a game without the Entity system now, so the balance is falling heavily in the other direction. The engine is aiming far beyond the Garry's Mod community.