I'll host this one for sure. If only to get to see the overwatch nation
A couple of suggestions...
1) I'm not sure removing Wish is really necessary. Players must simply not wish for the special units, that is probably sufficient. If anyone cheats it is likely the overwatcher will catch them anyway.
2) If the intent is for the Overwatch nation to cast Eyes of God, the Fate of Oedipus spell should probably be removed.
2.1) Overwatchers should probably get Eyes of God as starting spell.
3) A sufficiently large supply of astral gems would enable the Overwatchers to cast Astral Window everywhere, and eliminate the need for the spies entirely, other than for dome interactions.
4) Wish as a starting spell for the Overwatchers will allow them to conjure up deathmatches (and artifact prizes) at will. To prevent other players from using it (if this is still desired) it could be given an otherwise impossible path-cost. Reducing the gem cost in this case might be good too.
4.1) Could a player winning the deathmatch claim an already-existing artifact as a prize?
4.2) Maybe allow players winning the deathmatch to invoke other powers of the Wish spell, mediated by the overwatcher?