Its 75%.
And its easy to counter.
2 melee's because melee goes through the shield.
Or witherhoard.
Or div.
Or stay at mid-long range.
And you can shoot rockets next to them.
So use divinity or witherhoard (or heavy... just going to pretend you didnt say that), which are two horrible weapons, for the sole purpose of kind of, in some instances, being able to counter a glaive.
If a weapon's only counter is putting on another weapon that is useless aside from countering the first weapon, the first weapon is objectively not balanced. Its like saying "Snipers are op? Put on a scout rifle"