I am no expert. I do have a couple of thoughts.

Most improvements are margenal at best.

Decreasing the mass of all moving parts will improve the bow (if you think faster is better).

The bow itself shouldn' t get much lighter. Equal and opposite reaction thing. If the bow is too light, it will be to unstable when arrow released.

There is aleady a movement to parellel limb design, this makes the limb movement have less of an effect one the bow. It also gets the weight further from the center of the bow. The longer moment arm makes the bow more stable.