I'm no Pro Ladder material, but I have noticed a couple of key weak points in the current reveal.
1) Setting Cantarella to 1 is cool, but aside the long required setup, it's not automatic to reap huge benefits.
First, if you make Cantarella weak, it means you are not weakening one of the enemy units, somehow limiting the benefit of an expensive setup.
('expensive' because you have to put in the deck 3 bronze units who are not Nekkers or Dol Banana level finishers)
Also, a lot of times I see a Cantarella being weakened I cannot avoid to think: "He could have just used it, it's round 2 and he's bleeding me, value doesn't change much".
But it looks like some people just read: "Hey, you can abuse the card by making Cantarella a 1 Power!!", so they do it without even thinking why.
2) Most of the time the mulligan creates a lot of dead cards. Golems, Daerlans, and now Venendal.
I saw people using ADC and a 6-power Daelan spawned in round 3, others choked on their Golems.
(well, you have to use those taunts in a way or another...)
The decks lack setup-independent finishers, and some guys waste all resourced on round 1.
It's just netdeckers being netdeckers and using something beyond them, keep using consistent decks and you'll prevail.