There's a discussion on
mordenkainen's disjunction here. One thing I thought was interesting was that Piratecat makes it a full round casting time spell. So people can try to disrupt the spell and/or escape.
Another point was that the spell was disproportionately harsh against fighter types who rely more heavily on their items and have lower Will saves. Perhaps the following might be a better way of handling it:
each permanent magic item must make a successful Will save or have its magical properties suppressed for 24 hours. At the end of this time the item must make a second Will saving throw using its base save against DC 15: if it fails the save, the item is rendered nonmagical.
A powerful magic item will have a save of about +12; it fails only 10% of the time. Cheap items will fail about half the time (save = 2 + CL/2).
Or maybe have MDJ work normally against spell completion and spell trigger items, but not against other items. Or work normally on most items, but not weapons and armor. This is just an attempt to level the playing field so that fighters and barbarians aren't disproportionately hosed.
Hmmm. Maybe I'll post this over in that thread.
[edit] While I was composing the post over there, I thought that maybe weapons and armor should get their enhancement bonus (including special abilities) to their save. In which case a DC 20 would be fair. PCs would be hesitant to use it promiscuously, for fear of destroying loot, but fighters wouldn't be hosed if they were on the receiving end.