The fire drills in FOTS is somewhat lacking. There is only one drill - the kneel firing, and it is rather cumbersome to use since it has to be turn on/off manually. That leads to a few annoying things to happen: when kneel firing is turn on, it won't also turn on the guard mode by association, resulting in supposedly "locked down" troop suddenly abandon post and chase fleeing enemy against your wish, or routed troops which have just finished recovery ignored your momentary order to turn around because you aren't aware that they are still under locked down. Kneel firing also have weird animation in that the first rank kneels and fires simultaneously rather than doing it step by step. Furthermore, it was 1850s and there were certainly more fire drills than just kneel firing. While the DMS thankfully brought much-needed realism to the FOTS' (in my opinion) incomplete combat mechanism, the glaring problem in fire drills was sadly left unfixed. Hence, here's my proposal:

(I am aware that there's a firing by rank minimod available on Steam workshop. It is good but I found myself keep using the kneel firing due to muscle memory.)

Three firing mode: default firing, kneel firing (toggle on/off), firing by rank (replace the default firing upon research, like in Empire)

Kneel Firing
1. The first rank should automatically kneel down as soon as the regiment cease movement.
2. Troopers should not fire individually after the first volley. They should always fire in a grand double-ranked volley. It gives the player the option to choose between a drill with slower but greater volume of firepower (kneel firing) or faster but just half of the firepower (firing by rank).

Add Firing by Rank
The minimod did a great job of recreating Empire's firing by rank into FOTS, but I do think it fires a bit slowly. We may need a greater rate of fire.

Add Platoon Firing? Fire & Advance?
I am unsure wherever or not these tactics were in common use in 1850s Japan, or by the European armies for that matter. It would be fun to introduce them though as the modern breech-loaders would make both techniques much more effective than in Empire.