AFB (and have been for more than a year now), but I remember a Battlemind U22 that allows line-of-effect and line-of-sight to everything within radius 20 EoYNT. I put it on my Warlock draft via Eternal Seeker epic destiny.
In effect, a ranged combatant can see and drop attacks through the walls for two turns.
Unless there's something about it I can't recall, it should earn a color.
Four issues for Perfect Eye:
Daily Power. That's bad. You can use it for one perfect combat, not multiple combats. It is very likely to be a power that's wasted because the perfect combat doesn't happen.
It happens at 22nd level. Again, bad. The higher the level of a power, the more redefining of every day it ought to be.
It doesn't affect your teammates - if you're in a combat where a clock starts ticking once you start the combat, well, you need your teammates to step in too. At which point, you get into the weird focus fire problem of perma-stealth.
Also, ignoring barriers(aka doors/walls) doesn't mean you ignore everything. Clouds of darkness, dark rooms, invisible creatures, creatures outside range in a big Epic-sized room, etc...
That's a lot of questionable problems - I'm sure there's going to be a corner-case combat where it is invaluable, but given you get just one utility with Eternal Seeker, wouldn't you rather take Cloak of Courage(Cleric 16) or Borrowed Confidence(Swordmage 16) - those are both examples of powers that completely change the rules of every combat of the day as opposed to a power that might corner case change one combat per day.