A few unit bugs not already on the list:

Horse-drawn artillery: Trying to limber up the arty sometimes freezes mid way through the maneuver. I've noticed this in two cases: 1, when the path of the horse drawn limber is blocked by an obstacle (eg wall) and 2, when the gunners have been involved in melee (with no casualties). Looks to me like the bug is to do with re-setting the arty's behaviour -probably related to buggy fire at will behaviour.

Light infantry:
1, in "light infantry mode", deploying a unit by clicking and dragging to form the shape of their unit causes the unit to face the wrong way! I first thought i must be at fault (and deploying them back to front) but after checking with a unit of line inf, i confirmed i wasn't. Clicking to attack a particular unit or move to a given location does cajole the light infantry to face the right way and they will then fire at will as intended.
2, skirmish mode for light infantry units. This basicaly renders light infantry useless (or very short lived) when deployed as a screen in front of the main battle line. Light inf have a longer musket range than many other units and so should be able to fire on the enemy, especially their line infantry, whilst out of the range of returned musket fire (i assumed that this was the whole point of them). However, light inf actually don't seem to fall back untill threatened by melee/charge range of the enemy. This means that they have to be micro-d to intolerable degrees in order to achieve their purpose of drawing the enemy on whilst remaining out of the range of returned fire. I suggest that the fallback/skirmish "trigger" should be coming into the firing range of a targeted or approaching unit -not an arbitrary distance of the enemy from the unit of light inf.

Cover:
I am wary of using cover in my games. I've found that units placed behind cover don't fire by rank and will not always fire at all either. This is obviously a major pain in the neck as you might expect your infantry, so deployed, to do some damage rather than absurdly sit behind the wall.

COME ON CA

Kudos to the OP for starting this thread...