I enjoy playing AI WAR 1 but have mostly lurked on the forums. However with the new one coming out I have been reading the design document in preparation to back the game.
One thing I did notice was the link to the forum on killing force-fields and the conclusion that they are going to be left in the game as is. Some of the problems posted about shields were not game-play related but GFX and CPU related. This may help.
I have a long commute to work and I had a slight idea while watching water droplets on the window.
Why not make (well at least planet static shields, mobile may not work) shields act like droplets of water.
Ergo if you put two shields together they merge up and become a single shield with a combined area and strength of the two shields placed in it.
You'd still have shields as they act now from a player perspective - sans some of the shield healing exploits. Ergo dump 10 shields on top of my command center for 10 million hit-points. Except now they would blob up into one super shield.
However you would only need to graphically display one shield. From a CPU point of view this would also be one hit box for calculations as well.