Looks like the EYEs have it!
Good to hear.In my Goblins of Eberron campaign I gave out the Eye at 7th level, and it was awesome.
The player in question liked the sound of an attack that renders him invis to the target, but he can get that with just the Moonstone Sphere. The Eye's at-will, for 2d6+stat (+5 enh) and OG 5 would be a bit of a last resort. The real attraction of implanting the Eye is the daily aura of clarity.At the level your party is at, will it's attack powers still be useful?
Plus the Vecna hot-line. At this level, I would have thought the player might aim to turn Vecna as much as the more traditional vice versa.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.