The idea is pretty simple. A mod that can simplify bricks down to keep the brick count down.
Ex:
2 1x1's next to each other are destroyed and replaced with 1 1x2,
8 4x cubes in the shape of a cube are destroyed and replaced with 1 8x cube
This is probably impossible, but i think it would be a cool mod. It doesn't even have to be all possible simplifications. Maybe just start with replacing two 1x1's with one 1x2.