I recognise that you've put alot of work into this mod, and I appologies for only giving it a one. I guess I'm looking to a different philosophy with mods that I load up; I expect them to be able to allow me to do additional things, and have more fun, rather than allowing the computer to do new things and assumedly have more fun intead.
I was quite dissappointed to go to the trouble of downloading and installing it up, only to discover that it didn't actually add anything significant to the game, beyond having enemies with guns and buggering up my framerate. If nothing else, I would have liked the opportunity to equip myself and my companions with the things, and to be able to do so early enough in the game to be able to build my skill to a usable level by endgame. This, along with the lack of a readme to explain all of this, before I got to download it explains the low rating that I gave this mod. If you change things, load it up again, and I'll be more than happy to give it a much better rating. To be honest, I think that you've got the beginings of a great mod, with the new guns and troop types, but at the moment I don't really see it adding anything to my enjoyment of the game.
With respect to the smoke, why not just use the default smoke that doesn't hang around for ages, and assumedly doesn't have the same framerate hit? Yes, the other smoke is more "realistic", but given that the only one who appears to be impeded by it is the player, it seems like a moot point. If needs be, you could even upload two item txt files with basic and "smokey" weaponry, and allow the player to choose which to implement (I'm assuming that the default particle smoke is still lying around there somewhere).
With respect to being one shotted by random balls (maybe I just have bad luck?), and balancing it all, I'd suggest that you base the damage and stats of those for the crossbows and deviate from there. Up the damage and reduce the reload speed, while dropping the acuracy slightly in order to achieve the effect you want. Personally, I would say that an accuracy of around 85 is low enough, with the additional variance coming from the skill level of the troops themselves. I recognise it is supposed to be harder, but doing it this way will also make it more predictable and easier for you to judge the end result, because you already know what xbowmen are like.
For the short range, high damage weapons, like the slugshot, I'd also suggest reducing the velocity of the rounds to about 70 as this will greatly reduce their effective ranges, as indicated in their descriptions. Just to mix it up, you could also consider making a weapon that does blunt damage (not "realistic", but maybe it shoots sand?)
I'll certainly keep an eye on how this mod develops and look forward to being able to give it a better rating soon!