They'll just dodge roll out of it without leaving their stamina pool too low to break free like a magicka character
How would you actually negate stam skills? If it affects all stam skills, how would mag break free, roll dodge, or block if not using ice staff?
What you are suggesting seems it would screw mag even more then it would stam. Now mag would have to contend with traditional negate on top of a stam negate.