Well i'm not sure i want to start this, it may depress me too much.
But as you suggested it ,here goes.
These are all the problems that i have seen with the standard skins that WA uses. The Eldar glitches were spotted using the Craftworld Iyanden army scheme, for some reason this shows them up much more than some of the other schemes.
(Edit)
Problems:
Land Raider - machine spirit does not show up at all on the in-game model???
Eldar Warlock - when viewed from the front his right arm does not meet with his body but leaves a small gap which shows up whats behind him
Space Marine Dreadnought - centre of the power plant missing (fixed by Mel Danes)
(Edit)
Pixel clash:
Eldar Guardian - on the back pack, the torso, the upper arms, the knee.
Eldar Warp Spider - around the eyes, the forearms, the legs, the feet and the knees.
Eldar Warp Spider Exarch - the hip joint in the armour.
Eldar Farseer - sides of the helmet, shoulders, forearms and the tips of the wing things on her back.
Eldar Bonesinger - shoulders, arms and the top of the back.
Eldar Warlock - shoulders
Imperial Guard Leman Russ - eagles and skull emblem on the rear of the tank.
Space Marines Weapons - assault cannon and bolter.
As i said some of these glitches only show up with certain colours and in certain colour combinations......odd.
If anyone has any others to add please feel free to mention them and i'll add them to the list.