Honestly I can respect the dissatisfaction with players using GMW for the enhancement bonuses and thus allowing themselves to stack every other imaginable effect on the weapons through enchanting. It really doesn't feel as if it is in the spirit of the game. Despite that though, it is perfectly viable from a rules standpoint. Obviously due to the Sage's ruling that the objects in a creature's possesion are considered to be a part of the creature a targeted dispel is the most effective way to overcome this spell.
My question here is why do I often run across DMs almost running scared on these boards? It seems the complaint races over and over again, how to stop players from taking certain actions, how to control them, etc. I can see a problem if a particular rule allows one player to dominate the other players thus forcing the DM into a position of making encounters that challenge that player and kill the others, or that are challenging to the others and cake for the player. But come on folks, the players run at a serious disadvantage in any game they are in. The Dm controls which rules are followed, how they are interpreted, what challenges are set forth, what and how many monsters, etc. There are quite literally no limits set forth for DMs other than the threat of players walking from the table. Players on the other hand are forced to operate in a very explicit set of conditions. If they kill your monsters too fast use bigger ones. If they breeze through your challenges make better ones. More, higher level, more devious, how can a DM possibly have trouble controlling their campaign no matter what the PCs do?
-Immort