Maybe when you get it by a frozen weapon that part of your body gets frozen, and you can't use that part for some time until you thaw out (eg. one of your legs frozen = can't move for 3 secs. one of your arms frozen = can't use the bow for a few seconds)
It will be cool if frozen robots parts are harder to cut through since there is an extra layer of ice to cut through, so a strategy would be to freeze their legs (so that they can't run around) or their arms (so that they cant attack or block with sword) and attack wherever they are vulnerable. Maybe the fire sword slices through ice like nothing.
There can also be an upgrade where you thaw out much quicker.