Attached is a patch that seems to work for me. Note that the increase in appeal for the improvements is essential here: early revisions of the patch didn't include that, with the result that when the granary was full, the AI deprioritised food, and then happily decided it didn't need that Aqueduct/Sewer System so much after all, with the result that cities ended up capped at size 8. It still sometimes builds other things in preference to the EFT_SIZE_ADJ improvement, but it gets around to it after what seems a reasonable time, making me think the adjustment factor isn't horridly imbalanced. It may be that we don't need to always rearrange workers with a full granary as if it was an emergency, but not doing so seemed to cause long delays in the AI deciding to actually use more production during my testing.

(file #17823)