I would like to make it cost more, then change it into make each castle and shogunate spawn 1 samurai once, and automatically spawn 1 samurai per about 7 or 8 minutes later. This can make it a permanent effect, but it won’t easily affect balance due to the long wait time. It could be a good investment for the treaty game.
Culturally, I dislike that Tokugawa exists in the game. He is a shogun, similar to a prime minister of ancient Japan, cannot appear in the new town/colony, not to mention there is even his grave as a wonder. The design about multiple daimyos is absurd too. They are the feudal landlords and warlords, so a town/colony should be only 1 daimyo as the leader and ruler for the people there. It’s also weird to have the daimyo have a real name, it needs a fictitious Japanese name in the game. For example, Masamune Date was already the lord of Sendai in northeastern Japan, and could not possibly be the lord of a new town/colony in the Carolina, New England, Yukon, or the Nile Valley.
It is really a shame that there are too many stereotypes and cultural inaccuracies in the design of Asian civs.
The original one is good and just need a little adjustment, not a big change.
Perhaps make it still can train up to 10 units at once but the training time needs 10%/20%/30%/40%/50% more when 6/7/8/9/10 units are training together.
I would just introduced a modernized musketeer-like unit and a modernized skirmisher-like unit, maybe named New Army Regular and New Army Rifleman and having good stats at their lower price, for the Chinese and Japanese to make them be more the 19th century rather than staying in the 16th and 17th century.
Then, make Meiji Restoration cheaper and change it into a revolution-like effect, turning every Ashigaru Musketeer into Guard New Army Regular, Yumi into Guard New Army Rifleman, samurai into 1 Guard New Army Regular and 1 Guard New Army Rifleman, Naginata Rider into Guard Hussar, and Yabusame into Guard Dragoon. Also, the Guard New Army Regular and Guard New Army Rifleman become available at the barrack for the Japanese.