I was just thinking about shields some, and I was wondering if we could come up with something new that hasn't been done yet for them.
First (before adding new features (which I understand would not make it into the official 3.6.10 release)) I think someone should look into how well shields work on capships. Basically checking what happens when the shield is big enough that someone could put their firing point between the shield and the hull--does it hit the hull, or go through to the shield on the other side, or what? And what is the 'correct' behavior--maybe some mods might want different behaviors?
Most of these ideas would probably not be used for or applicable to the main campaign, but instead in user mods.
Also, would it be possible to have multiple independently destructible shield generators on a ship (probably a capship), which when destroyed expose a part of the ship to damage? (It might be kind of hard to get this just right though. Projecting a polygonal mesh (like the current shields) might work, but depending on what the creator wants, it might look kinda funky.
Another, significantly more complicated idea would be to have shields that have a dynamic shape. For a single shield generator (or a ship that doesn't have a shield generator system), I was thinking of something where as you hit the shield quadrants, the shield over that quadrant droops closer to the hull. When it is at 0, the shield is on or inside the hull, and the shots will simply hit the hull itself. You could probably cheat somehow to simplify calculations by adding a slight randomization to the position of the shield hit effect, too. If this idea were to be combined with the previous scenario, it might be neat if instead of making meshes for each generator, each generator would have a bubble around it (calculated somehow), which would shrink and disappear as generators went down (and might reappear in an interesting way if a generator were repaired).
Other interesting ideas might be "shields" that reduce the strength of incoming weapons during the time they are inside (possibly a linear decrease in damage per distance/time, or an exponential one). Also, an effect like the "time bomb" that was planned for the Mothership in StarCraft 2 (an ability which I believe has currently been scrapped); it basically slowed down and stopped all incoming fire before it could reach the ship. (Of course, there would probably need to be some sort of counter for such a shield, and I don't know how beams would be slowed down (maybe they could be the counter))
Last but not least, something akin to the Gravitic Impeder in the game Battleships Forever; a subsystem which shoots out a beam of gravity (not realistic but it's a game, right?) which slows down an incoming projectile. It would only be able to target one or a few shots at a time, though, meaning if one were to direct enough fire at the ship some or most of it would get through.
Just some zany ideas I thought I'd throw at you.