Those sucky little colorful practice sheilds that take no difficulty, break quite easily, and are not very heavy or large in width/height.
I think they could possibly be made 0 slotted.
Reasons why:
1) It could give "Ranged OP" grievers an extra small protection against projectiles when their slots are maxed.
2) The sheild is a peasant item and would never be used otherwise.
This is a long shot but OK I put it out there.