Do you know what your water pressure is? Are you on a well, or have public water? If it is low, had you considered a pressure booster system? If on a well, had you considered raising the pressure?
While removing restriction generally will increase the volume, it might lower the ultimate delivered pressure. Having a restriction causes the water to speed up through that restriction...removing it too much, means that while you may have more volume, the velocity or force of the jets could decrease. Think of it like having a hose without a nozzle...max volume, but trying to get the stream to go very far often doesn't work...add some restriction (say, put your thumb over the end), and now the spray goes further, while it might reduce the volume.
FWIW, more volume out of the showerhead will generally mean a shorter time in a shower since you'll empty the tank faster.