I think if you asked the team whether or not we'd be happy if Yogg showed up in the tournament scene the answer would be yes. If players are building their decks slightly differently to play a 10 Mana 7/5 creature... I think the appropriate payout for that would be to swing the game at least in some circumstances. Cards like Lightbomb, combos like FN+DSayer have done that at even earlier stages of the game but I think Yogg does it in such a flashy way we tend to remember those moments more. That said, no one is very happy when one card / strategy dominates the entire format, but I think we're pretty far off from that for now.