Yeah I know, Pavise has been asked a lot of times, but I'd like to bring it up again.
As it is now, shields on your back don't catch projectiles. I am sure you know how this worked in history: Pavise crossbowmen had these big tower shields on their backs, facing the enemy with them while reloading, thus giving them cover.
So, I've been thinking: What about a deployable Pavise, that you can only wear on your back? It should be the ONLY shield that catches projectiles on the back, to a certain degree. I know this might be abusable, so it should have a nice huge weight and some skill investing should be required to make it usable, so no tincans would use it on their backs.
This is where I'd like to bring in two other ideas, A crossbow expertise skill, that works on accuracy/reloading, to access of heavier crossbows, and a bit lowered upkeep. Also, with a crouch system in, pavise crossbows would be actually quite useful if deployed correctly.
What do you think? It would make crossbows different, well better than the "shotgun" they are now.