Frost knuckles already made ice staff redundant, why do we need another, unless it just has really high stamina but then it's pointless. Instead maybe make it only take 5 stamina but slows zombies down each hit, but every 3-4 hits freezes.
It would freeze every few hits and would also act as a low stamina weapon to get away, therefore boasting slightly more utility whilst having a slightly nerfed freeze. Freezing weapons aren't that useful unless you're playing rapid infection anyway and it would add a new dimension to the arsenal of melees by having one which also slows zombies down.
Instead of zombies/enemy players getting instantly frozen by just a stab, the weapon could just trip and slow down the zombie's walkspeed. However, it could do a unique move (similar to toy hammer's super smash) that could instantly freeze enemies around the player but at the cost of both stamina and walkspeed.