No time to play it. But I browse the subforum sometimes, and his commentary and detailed analyses are very good. I think Éa is a more radical departure from base particularly regarding growth. Making non-resource tiles not sustaining (or only barely so for Agrarian) turns everything else on its head.
I'm not sure that I read what he has written about gold/production balance. I want to try to even up the different yields as much as possible. The basic idea is to devalue 1 production a bit (by making it more available and/or inflating production costs), increase value of 1 gold (by doing the exact opposite), and so on for each yield type. It's not really essential but it simplifies balance and also AI valuation (the AI values yield types as basically equivalent, although it would not be too hard to add a correction factor for each yield type).
From my time with your alpha, the food per population is as large of a change to the game dynamics as your dynamic civilization trait system.
It completely changes EVERYTHING, it forces you to be much more careful in city plot selection... and those early food resources (whatever they may be) in turn define the early development of your civilization, and which name you get.
It's the first CiV mod I've messed with that didn't feel like CiV.