That's a really sweet card; I like it a lot. It also has the nice touch of being a two-edged sword; sure, your opponent can't firebolt or heal or earthquake or play any other spells, but neither can you. Of course, in a properly-built deck, this will penalize your opponent far more than yourself.
I think that this should perhaps have some sort of duration on it, like wings, cloak, dimshield, etc, maybe 4 turns? That's more just my dislike for absolutely unbreakable combos coming out, though.
Re: RRQJ: Isn't that exactly what the card is saying, that you can't RT, explode, steal, adrenaline, black hole, etc? At least that's how I'm reading it.