This one has been proposed in many forms before, however, as far as I know, this particular proposal is a completely new and original version and any thoughts on improving it are certainly welcome. Each city starts out with a single build queue, but various technologies unlock additional build queues. Using just one queue, it works at 100%. Using two queues, they work at 75% of total hammers produced by the city. Three queues work at 50% and using four queues work at 25% of total production.
Ill illustrate with an example. Lets say a city produces 10 hammers per turn. If only a single queue was being used, youd produce a total of 10 hammers per turn in that queue. Use two queues and you have each producing 7.5, or 8 hammers per turn, for a total of 16 hammers of total production per turn. If you use three queues, each would produce 5 hammers per turn, for a total output of 15 hammers. And if all four queues were being used each would produce 2.5 or 3 hammers per turn, for a total production output of 12. This has the same problem that every other proposed multiple queue system Ive ever seen proposed has had total production falls with more queues.
Since production totals drop with each additional queue after the first, the obvious thing to do here is to always use two queues. This is not what should occur. I want to encourage multiple queues being used, so additional bonuses need to be given. With one queue there is no bonus, nor is there one with two queues being used. Once a third queue is used, a +1 is added to each queue, so that you produce 6 hammers per turn, for a total output of 18 hammers from the example above. Then when a fourth queue is being used, a +2 is added to each queue, so that you produce 5 hammers per turn, for a total output of 20 hammers from the example above.
This system encourages the use of multiple build queues, since total production continues to increase with each queue used. It also illustrates the fact that total production has increased throughout history, making it more efficient to produce in a large scale.
......EDIT......
Scratch the above...
Techs unlock additional build queues like I suggested before, but your original queue is always at 100%, the second is at 75%, the third at 50% and the fourth at 25%, making it the slowest queue to build in. So for example:
If you have a city with 10 hammers per turn, you'd have these four production amounts in each queue...
1. 10 hammers
2. 7.5 hammers
3. 5 hammers
4. 2.5 hammers
for a total production of 25 hammers per turn.