in tessourse there is a mod that with obse 11 you can on keypress toggle your weapon to attack like a spear in my theory one could use the structure of this to make weapons with their own animations such as a Crossbow or trowing knives.
heres a linky
That looks and sounds interesting. I think there might already be a few mods that bring spears into the game, but I've never really looked. :/
I don't know if this can be used for any other weapontype. As far as I know it toggles a bug that let you use bluntskill to do damage while playing the staff attack animation. The mod is limited, it can't trigger a sneakattack, it's really slow and has some minor bugs.
^ In Morrowind, I didn't know how to create a new weapons class so I tried making spears a single handed weapon by making it a "single handed blade skill," It was weird but the animations turned out ok.
I'm not sure but they should have a mod that allows you to add weapons classes or import weapon classes (and animation) from Morrowind.