I like the point about the Changdao but I prefer their mobility. I think they would be much stronger if they could get that Military Drummers upgrade and get 5.5 movement speed. That would make them even more effective. I, personally, use them to assault artillery and defend against cavalry. Like, if my opponent wheels up their artillery to strike at my like 40 Arquebusiers, I hit the spaced-out formation and while that’s happening, my Meteor Hammers and Changdao come from two different directions, sometimes going through the loosening of the Arquebusiers. When fully leveled they have a high attack too, like 40 if not more BUT I think they should have an upgrade, like with Manchu combat that gives them a 1.5 multiplier against infantry. That would really round them out but that might make them overpowered.
And the Banners, I disagree, I never have dead weight from my armies. I especially love waiting to send like 20 Steppe Riders and 20 Keshiks. Like, I will wait till my enemy engages me closer to my base and if I appear to be winning, I will send the Steppe Riders straight towards my enemy’s base and use the Keshiks as escorts. It’s a super cost effective method too and if I am extra cruel, I build 4 mountain castles on the edge of their base and I can just swarm them. Granted, some civilizations are way more resistant to that, like Russia. Their Strelets body Keshiks and while the Steppe Rider gets a damage boost against infantry, they can be easily overwhelmed without fire support or just attacked by cavalry archers or halberdiers.
HOWEVER, your idea about scrapping the Banner Army system altogether gave me an idea. There could be a card called “New Army Creation” or something more accurate to the Beiyang Army. They were 2 full units that the Qing government created and modeled entirely on Western designs, using Western style uniforms (albeit, with the Manchu cap and the obvious Chinese colors, whereas the Japanese straight up just took German military uniforms). That could be a “revolution” of sorts for China. It removes the Banner system, and can transform the Arquebusier into a stronger, Beiyang Infantry, or something, just thinking.
However, it is worth noting that the poorly supplied New Army was involved during the Sino-Japanese War where 600,000 Chinese lost to like only 200,000 Japanese. This is also noteworthy because Yuan Shikai, field marshal of the Beiyang Army REFUSED direct orders to march because he was not willing to risk his army (he was involved in dethroning the last Qing emperor, declared himself president of China, then emperor, then died in 1916, then Civil War resumed). So idk, Beiyang and New Army upgrades might suck lol.
The Grand Empress Dowager, Cixi, she embezzled so much money from the New Army that they had almost no supplies during the Sino-Japanese War. That and like 50 years of weak leadership led to an army lacking leadership. All the good generals had passed away like 10 years prior or were super ancient by 1895.