Instead of shield disarm, why not change it to offhand disarm? This'll allow people to knock off offhand weapons, staves, etc. Allows more versatility.
Shield Disarm
there is an off-hand disarm though only 1 or 2 classes that I know of have it.
Aside from questclasses, only warrior gets offhand disarm.
Battlemage can use localize gravity on a secondary weapon as well.
I think he means make it a "general" off-hand disarm, and not a "specific" off-hand disarm.
So like, the new off-hand disarm that Goomf is suggesting will disarm ANYTHING in the off-hand. Be it a shield, weapon, wand or whatever.
You can disarm anything with localize gravity, much like Goomf suggests. Probably because what you are doing, is "localizing" the gravity so that anything is pulled away. The other classes, with shield-disarm however, are trained the "combat" uses of disarming. That is, they know how to disarm weaponry, and shields, but don't know the techniques behind disarming wands and potions and staves etc. That's the RP way I look at it.
Also, by turning shield-disarm into off-hand disarm, that means that classes like Paladin, would have dual-wielded weapon disarm like what Warriors have, and would make the warrior skill of off-hand disarm defunct.
Dey