Great card
I think it should either cost more, maybe 8//7 (like sky blitz/fractal/miracle do) or else last for 1 less turn, as I think it is undercosted. The card idea itself though should definitely be kept.
And yeah, I suppose since Sanctuary protects against Silence, it should protect against this, too, although neither Silence nor this actually modify the hand in any way, they prevent cards from being played, which is actually the opposite.