To my knowledge, some sergeants in some armies were using halberds and spontoons as a badge of rank. So they could potentially be added. According to Wikipedia they persisted into the "mid to late 9th century." Also, many officers used non-regulation sabers throughout this time period, so they could be added if we wanted more sword variety later. Also, as someone who knows how to use a Highland Broadsword, options without something other than the red velvet will always be appreciated.
And for those without much familiarity in the period may find this website interesting:
First you have to choose a speciality. (Cavalry for example)
At the beggining, you are a simple soldier. Like Freeholder mod.
But as you promote, you gain more soldiers under your command. But you don't command all the soldiers. Only a little part of it and the speciality is very important so if you choose cavalry you can only command cavalrymen.
At the last rank, you may command half of the army or more.
You have surely noticed that my English is not great but I hope that you have understand most of what I wrote. (I can explain another time if you don't have understand)
You may receive some instructions (just the big lines) from the big leader but you can still have a little freedom to organize your troops.
I think this suggestion will add a lot of realism and fun to the mod and it will give a meaning to the rank system.
Here's a small thought. I've been playing French for the past couple of days, and I find the infantry troop tree a bit weird. The troops themselves are fine, but the upgrade branching is what irks me.
Wouldn't it make more sense for Grenadiers and Voltigeurs branch out of the Line Fusiliers, rather than Fusiliers and Grenadiers from the recruits, and the Voltigeurs out of the Fusiliers? I'm unsure of how it was in real life, but from a gameplay standpoint, I think it'd be better if you start off with the standard balanced troops, and then pick specialisations for them as they level up.
The same could be applied to the Light Infantry. IMO, the branching should go Leger -> Chasseur -> Carabinier/Voltigeur.
As for the Guard units, I'd prefer if the troop tree could follow the historical "progression", being everyone starting as a Tirailleur, then a Middle Guard Fusilier-Grenadier, and finally the Old Guard Grenadiers.
Of course, this is nitpicking at something not really relevant. It would make getting Old Guard Grenadiers much harder and expensive, though, but I think that fits the Imperial Guard.