https://www.fantasyflightgames.com/en/news/2018/5/4/the-wizards-quest/

We finally have a good competitive format! This will probably increase the errata harshness and frequency, though.

This only use the 2013 competitive rules. There is nothing new in that, it only enforce them. And I expect the game to stay played cooperative way by 99,9% of players.

There's one new thing, there are cards that the opposing team has input in. Meaning, they can choose how the effect resolves against your team. Also they get to design your encounter deck I agree most people will play it cooperatively at all times, but I would estimate the percentage at 89.9 to your 99.9

Anecdotally, there are those in my group, including myself, that will be happy to take the competitive encounter deckbuilding for a few spins, so count us in that 0.1–10.1%!