I'm currently building a small town in Minecraft, and am annoyed by the way Luminators currently have an internal storage unit without the ability to turn it off/take it out. I just spent 3 hours trying to design a light detector using solar panels, MFE's, mass fabricators and redstone repeaters, to end up discovering that Luminators won't turn off when the current is removed because of their internal storage.
I would like to be able to use Luminators like real lights, so they turn off when a current is removed, and turn on when a current is applied. This would be useful for my street lights in my town, as well as being able to build a mob spawner that can be luminated when not spawning mobs, etc.
I know in MineCraft 1.2 we now have Redstone lamps that fulfill the same objective, but Redstone is not as easy to use as IC2 cabling, and not as flexible either.
I'm not suggesting that the internal storage should necessarily be removed, but maybe adding a GUI with the ability to turn it off if you don't want it.