I don't know why we can't just do what MoM, MOO2 and Civ did. Give us the option to assign citizens to city production or the military (guns or butter). It worked fine in the past, why fix what ain't broken?
Reduced 98%Original 579 x 425
That has historically worked out fine. I'd say we can do better, though. I'd consider Brad's specialist idea, Sethai's direct proportionate idea, and my hybrid idea, are all more interesting from both a gamist and a simulationist perspective.
Also, doing something just like what's been done in the past may not necessarily move many games.