Lots of decks beat it. Both OTK Mage and Druid are decks that either don't get their combos off, or are impossible to beat, so those are options. I just played as Paladin vs OTK mage and was frozen for 8 turns straight.
Pain Warlock can fairly consistently get a very strong board by turn 4-6 and can be too much for them to deal with. Make good decisions with the order you play things in and you can roll over paladin and druid. If you draw badly or mess up with what you play and when or they get really good early draw then they can take full control but it's such a fast, aggressive, value generating deck that they don't build up enough steam.
I've played paladin less than druid so still need to see how it goes as part of a larger sample but it's gotten to the point where if I come up against druid then I'm pretty comfortable that they will lose. The ramp just kills them because it's too slow.
I've been having success with Commencement Warrior. There's enough control/removal that you can usually grind through their Divine Shields, and eventually your top end is just superior to theirs and their answers are exhausted.
Especially hilarious if they're running Duel!, because it plays right into your own deck's strengths. I've never lost a Duel! yet, and I've had several Duel!s where my minion was either Deathwing or Kargath Prime.
Priest works great. Once the meta settles, priest will be one of the best classes. This is shaping up to be an expansion where hard removal and silence are at a premium, both of which priest excels at. Warrior is also in a great spot but lacks the silence which sometimes is necessary. Nothing like watching paladin buff a minion with all their librams then having it all come crashing down with a zero cost spell.
Shaman with devolving missiles, hex, plague of murlocs and earth shock makes short work of pure libram buffing paladin
All of those are decent but Plague can backfire sometimes (they can get pretty high stats semi regularly). Diligent Notetaker is really nice here as well for the extra removals as well as Wandmaker and Cobalt Spellkin