In a game that had disarm as an action (3e), it didn't come up that often. Mooks weren't running around disarming everyone. There was a few heroic moments like when the captured PC hero was forced to fight a stone gollum bare handed and he disarmed the gollem's adamantine sword and destroyed it with its own weapon. That was epic.
I don't want to ban that kind of thing from my game and, from first hand experience, I know it's not going to turn into a disarm free-for-all. It just won't.
And, actually, locked gauntlets was a thing(in 3e, at least. I'm not sure about the real world). People didn't use them much because they had a significant drawback that You just can't draw any other weapons or potions or do anything with your hands (like stabilize a fallen comrade). So, if I were to put in undisarmable magic weapons in my game (which I wouldn't because they'd be totally unnecessary), I'd give them a similar drawback.
But as I mentioned above, you don't have to like a rule to help someone make one up for their game. If you think it's not balanced, then that's fair enough. No need to expand any further. It's just not helpful to tell someone "I hate that" when they are looking for feedback for how to do something.
[MENTION=463]S'mon[/MENTION]
What did you think about using passive attacks as a base DC? I'm wondering if that dc is too low. If you want to make it difficult, and want to use disadvantage, I'd attach a reasoning. Rapiers aren't designed for disarming, so disadvantage but a sai doesn't have disadvantage.
I also think there should be a drawback for disarming otherwise it takes away from the uniqueness of the Battlemaster. A battlemaster should be good at disarming and shouldn't have a drawback. Meanwhile the Champion, risks losing his own weapon if he tries it. (or something like that).
Despite liking disarming, I have to agree that it shouldn't become so easy that it's commonplace. I think 5ekyu has a valid concern.
In 3.x iirc barring taking feats to boost your disarm, attempting a disarm gave you an AO - that seriously cuts down on the merits.
In 3.x iirc disarm was done instead of an attack causing damage, not just an add-on to an attack that will damage.
Both of those are major game changers to the usability of the disarm and viability of it.
So, the experience with 3.x vs the benefits of this thing is not even close.
They share the word disarm and depriving the enemy of weapon, but little else.
Key Point for Analysis - just cause two different games use the same word for something - that doesnt mean they are comparable by nsme alone and the most basic simplistic not even thinking 101 analysis needs to look at more than the name to choose how to compare them.
In 5e, when you use attacks to get other effects as genersl maneuvers - shove and grapple being good examples - its not just added onto your damaging attack.
Magic Items Design - So, if someone wanted to enchant a magic item to prevent disarming, you would require that magic item ti have significant drawbacks? Did you add significant drawbacks to all magic items?
If not, why insist that a magical counter to disarm get them? After all, it sounds like disarm is a minor thing, so why force a significant drawback on an additional feature you describe as "totally unnecessary"?
To me, when folks want additional effects that are minor, maybe good for flavor, but which are certainly in the impact of "totally unnecessary" i let them go pretty easy. I dont go all "must have significant drawback" on rather trivial effects.
But hey guess it takes all kinds.
And if all you get from this is "i hate it" , seems pretty dismissive of posts you dont like which had a bit more than that in them.