Generally, I think you might have trouble getting responses to this – expecting people to watch about three hours of videos is a big ask. (Although there’s a lot of filler and you can skip through to the details – which is mostly what I did.)
His designs are clearly a labour of love that he’s put a lot of thought and effort into. Generally I think there are some interesting ideas in there, but they tend to feel a quite unbalanced. Here’s what I make of the individual designs.
Gaels
Given that Celts are already in the game, adding Gaels seems excessive. Some parts of the design feel like a different way of executing the same concept as Celts anyway, e.g. the sheep bonus. They specialise in defeating infantry, which seems too niche, and I think they’d really struggle against archers.
Zapotecs
These seem like a sensible choice. I like some aspects of the design, particularly the faster moving/attacking Eagles and the free unique unit upgrade. I think he overestimates how good Monks could be as a substitute for late-game siege weapons, especially since they have no Sanctity – you’d just end up using Trebs instead. Also, the civ seems to be hard countered by infantry.
Swiss
I find this design kind of odd, to be honest. They’re missing the Imperial Age upgrades for their Arbalests, and are instead supposed to transition into their unique Arbalest that sort of covers for the lack of upgrades but has a shorter range. The Imperial Halberdier seems less interesting than other Swiss Pikemen suggestions I’ve seen (which usually involve +1 range).
Georgians
I really like the idea of cheap Dark Age Stone Walls, but I know a lot of players would hate it! The Monaspa (anti-gunpowder cavalry) seems much too niche, especially in the Castle Age when there are almost no gunpowder units to counter. I don’t get why having good Light Cavalry means they shouldn’t have Heresy – who counters Light Cavalry with Monks?
Cholas
These are effectively in the game now anyway as Dravidians, who I think are a more interesting way of executing a similar concept. I think the Galley line bonus (+1 attack and range) would be too powerful. I don’t like the idea behind the Chinese Engineers unique tech – why would having Chinese engineers give you something that Chinese themselves don’t have?
Vlachs
I like the idea of the Skirmisher bonus (+1 attack per age), but I think I’d prefer to see it for an American civ. Otherwise, this design feels a bit all over the place – it’s labelled “Cavalry and Infantry Civilisation” but it’s more like a Cavalry and Infantry and Skirmisher and Siege civ. Also the word “Flailman” sounds really goofy.