Cool Card Design of the Day
12/15/2016 - It's rough when you have to spend four mana to Sleep Paralysis a two-drop. Hold for Questioning tries to make you feel better about that by repaying you the mana over time.
That achieves our goals best, but we can simplify it so much at the 'cost' of opening it up to work on any creature.
And in practice, if you care about the mana you'll want to cast this as early as possible, so we're still effectively hitting our design goal.