There's two major things that need to be dealt with. One is the sliding issue with cannons, they are still barely moving after you let go and if you grab them again they bounce everywhere. Same thing with limbers, I literally had a limber sling me back 10 feet when i walked up to it to grab a round, no one on it and it wasn't moving.
Second, the UI at the rear of the gun in a pain in the ass. Trying to pick prime or elevate requires you to almost have to look out of the corner of your eye at what you want and if you move a fraction of an inch you still select the wrong one. Same thing on ammo, I've looked at a shell round, barely touched my mouse and grabbed case.