It's not like OTK decks are impossible to build, but the reduction in board clears and tech options makes succeeding a lot harder.
For example, pulling off mecha'thun is still possible in most classes, theoretically. I know warlock, warrior and priest can still do it for sure. Hunter can do it too but has to reduce cost three times, rogue can do it, druid can do it too. Shaman can do it in a roundabout way (8 card combo). But possible and viable are two very different things.
It's not like OTK decks are impossible to build, but the reduction in board clears and tech options makes succeeding a lot harder.
For example, pulling off mecha'thun is still possible in most classes, theoretically. I know warlock, warrior and priest can still do it for sure. Hunter can do it too but has to reduce cost three times, rogue can do it, druid can do it too. Shaman can do it in a roundabout way (8 card combo). But possible and viable are two very different things.