I disagree that this is balanced.
The loss of high-level magic items at this level is a serious handicap. You're talking the loss of between 3 and 5 from attack & damage (in the case of weapons & implements) or the same amount from Reflex, Fortitude, and Will defenses - and the potential loss of various energy resistances! The ability to do this multiple times in an encounter is pretty much a recipe for TPK.
That said, here's a language revision on your proposed alterations:
Aura of Greed - Psychic
Standard Action, Encounter
Close Burst 10
+35 vs Will 3d10+10 psychic damage, opponent stunned and takes 15 ongoing psychic damage (saves ends both)
GIVE ME WHAT IS MINE! - Charm
Standard Action, recharge on a 5 or 6
+35 vs Will, Target drops his highest level magic item in his square. The dropped item must come from one of the the following item categories: weapon, shield, head slot, arm slot, feet slot, neck slot, hand slot, waist slot. If target possesses more than one "highest level" magic item, randomly determine which item is dropped. Target is dazed until the LoG's next turn. The target cannot retrieve the item (save ends).
Your language here left too much open for interpretation. The definition of "best" magic item can be debated until the cows come home. "At the dragon's feet" implies the target must move adjacent to the Lord of Greed, which could bring the target into the Inferno aura.
Farland: what do you think of the italicized language? Too specific, or does it properly address issues with dropping armor (or other body slot items)?