fields can't not be built within 50m of CC in CWA if you want to see what its like

I think your advantage were forge upgrades.  The AI did not get any of them until it was too late in Endgame. Nevertheless the german 2 slinger brigade trained from 2cc were two unbelievable lucky guys.

Regarding your first line, not allowing fields next to CCs was discussed not long ago, I don’t know what was the conclusion. I think it’ll be implemented at least in one mod for now. Regarding your second line... I'm confused about “storage actually contains resources”, RTS don’t tend to work like that… not that that’s an invalid mechanic, just that you are stating it like it’s the obvious default, if I even understand correctly what's going on.

I'd be happy to start working on a template and spin up a demo on my server.

Not that fast to get it from a video, but from its wiki: "As the player advances through the ages, and erects more structures within the city limits, the city will expand, increasing its defensive power, gather rate, and extending the national borders, as well as its own radius". Indeed I had forgotten, this is a really nice mechanic, I prefer it to going village->town->city for all CCs at the same time. What ruined RoN for me was the automatic transport ships after building a dock.   I think I've read this being discussed, and indeed it would be worth having the option, no need to impose one or the other.   I don't tend to agree with this, because there are many ways in which something can work, and no one resonable proposes "change this without any testing, because it works in my mental emulation".