Arcane Breach functions a lot like Mystic Denial except that you'll get to draw a card instead of getting an additional interrupt. This is almost a staple card for PVP and most of the official raids- and it's an uncommon to boot. The automated raids have nothing to interrupt and rarely use the chain, so this card would be pointless in my automated raids such as Ulduar and Ahn Qiraj, or the dungeon deck Utgarde Pinnacle I designed. A good card for old raids an PVP, definitely. It's what makes mages annoying.