It would be beneficial to have the project modularized.

First of for that a requirement would be to have a Brush API that let's you register brushes externally.
Since this was in the planning for external developers to hop in and make their own Brushes this is a go in my opinion.

Secondly this would allow for deep testing the API on every change we make, because the API would be used by ourselfs.

With this we would allow users to roughly define what they actually want to have on their servers, as well as help us distribute quicker fixes and distribute our efforts more easily, since the code is heavily modularized.

Since this requires the project core to be well programmed, it would also enforce better code.

This is now done with the advent of VoxelGunsmith and VoxelSniper implementations for various platforms.