I rather agree with the OP on this. The "reeling" effect is okay at best for something so rare and one of a kind.
The breaking other items idea is pretty cool (though I'd make the chance to break other items higher) but I'd even settle for what is established in 5e.
Adamantine Armor
COMPENDIUM - SOURCES->DUNGEON MASTER'S GUIDE
Adamantine Armor Armor (medium or heavy, but not hide), uncommon This suit of armor is reinforced with adamantine, one of the hardest substances in existence. While you’re wearing it, any critical hit against you becomes a normal hit.
Adamantine Weapons
COMPENDIUM - SOURCES->XANATHAR'S GUIDE TO EVERYTHING
Adamantine Weapons Adamantine is an ultrahard metal found in meteorites and extraordinary mineral veins. In addition to being used to craft adamantine armor, the metal is also used for weapons. Melee
weapons and ammunition made of or coated with adamantine are unusually effective when used to break objects. Whenever an adamantine weapon or piece of ammunition hits an object, the hit is a critical
Another idea would be to give this items the "disarm" effect passively when you strike an opponent you have a chance to disarm them regardless of their weapon is magical or not or in the case of armor when struck same thing.
either option is better than the -1 to attack rolls that the current "reeling" does, especially for how hard the fight to obtain the item is.
Just as a point of comparison to another weapon that can be hard/ risky to obtain: the Everburn Blade (can be dicy because if you don't time it right the mindflayer will turn on you and kill you.) what it offers for the risk taken is MUCH better and it is considered uncommon while the adamantine gear is considered rare?
