Master of the Guard drops 2 earrings, 1 for caster & another for melee. The warders drop both a caster & melee earring, but only one very rare all/all illusion ring (which I've never seen from over 20 kills). Sleeper drops an Earring (which seems to have a higher droprate) & a ring (lower drop rate).
My suggestion is this:
Make the MotG earrings equippable on both ears & fingers, BUT AT THE COST of 20hp/mana. Call it "Amulet" instead of "Earring". So instead of a 490hp/mana/end earring, it'll be a 470hp/mana/end amulet (ear/finger)... reasonable suggestion, right?

-edit- the clicky effects can also be removed to further balance with the slot/equip flexibility.