One of the more annoying things in GC2 was that you could lose a non-trivial amount of production because the building/ship you were making wasn't an even multiple of the planet's protection, and any excess would be lost.
Civ3 has this problem, too. Civ5 fixed it, by assigning any "excess" production from that turn to the next item in the build queue.
Please do this in GC3. Especially now that you've unified the build queues; having to constantly micromanage production amounts on each world to avoid this kind of lossage was a major annoyance; in fact, one of the biggest annoyances I found with GC2.
