Smoke shells were added for tanks a while back, which I think was an excellent addition. Sadly not many people use them.
The AT field guns are often used for long range support, especially on maps like Normandy and Tunisia. While they can be very useful both against tanks and infantry, I feel like they are missing out on some potential in terms of support. Smoke shells as a third ammo option from them would be incredibly useful.
Especially as the other smoke options of grenades and even artillery smoke don’t really put up very large clouds, whereas the smoke shells do.