Er, Exemplar, re: Japan's Coastal bonus, it is indeed very rooted in history, if not Hojo's time period.
In the struggle in the mid 1100s, there was a brewing conflict between the Taira and Minamoto families over control of the Imperial house. (IIUC, the Taira had supplanted the Fujiwara in becoming 'hereditary uncle to the Emperor'--don't ask--and thus controlled the Japanese state.) There is a lot of gory history, but it culminated in the Genpei Wars (again, name may not be exactly correct) with the Minamoto's power base being the Kanto plain and its better horses, while the Taira had a lot of veteran coastal naval troops. Indeed, it excelled at amphibious operations in almost the exact style suggested by Hojo's ability.
Eh. That isn't what that ability says to me. It doesn't have much to do at all with amphibious operations (which there is a promotion for, or norway's abilities). It just means if their warriors are standing on the coast, they're magically more resistant to arrows, and somehow fight better with the sound of the waves. It doesn't matter what they're doing, just that there is a magical aura on the coastline where they're randomly tougher/stronger, and power down when, say, they invade mainland China.
Veteran naval troops suggest to me the cliff scaling and amphibious promotions, or being able to land and attack. Being better at land wars
here but not over
there doesn't show off anything about a naval army tradition, just a weird gamey bonus because they couldn't think of anything better after Norway came up in the design meeting.
Though I admit part of it is a personal distaste for circumstantial bonuses that fall apart if the map isn't ideal, especially since the ability to customize what civs appear isn't in the game. If you start up a pangea game and Japan turns up, you're automatically up on them, because one of their traits simply won't really apply.
Back to the civ analysis-
Scythia has turned up on Marbozir's channel. Bonus horseman are nice. Fast, tougher slingers are nice (horse archers), though he missed the fact that the +100% cavalry production card doesn't apply to them since they're ranged units. Bonus vs wounded and healing on elimination... all those make for a steamroll early game.
But... mid game, i don't know what this civ does, and we aren't likely to see it in these videos (he did tiny & quick to push out one last series on the press build). The horsemen and horse archer probably won't do well once pikemen and knights are on the field, and it is a long wait until cavalry. The bonus vs wounded isn't that great a trait that it can carry the civ from medieval to industrial era alone.
The Kurgan, though... that is coming across as pretty useless. Having a couple strategically later on can help push having more faith dollars, but they come at the cost of growth and housing, and the AI suggests them almost universally over farms, which is terrible. Actually using them in the early game can really cripple your growth.
. Technically you only need 4 techs from the start, but you will probably pick up Astrology and Celestial navigation for the Harbour. Someone mentioned this another thread but seeing is believing 
