I think I might be able to take a single rogue, but they usually gang bang me with multiple stealth. A solution to these surprises would be an on use sleet storm aura that radiated out from the frost mage and put visible material on the stealthers.
Once this happened, they could be seen visually but not targeted directly or tab targeted, but they could be hit with standard AoE to knock them out of stealth.
OP? maybe, but who cares, it would be nice to have.