I've also been enjoying the beta a ton. It's important to mention that the beta only touches upon some kind of story/episodic element, the difficulty levels were something they were working on, and the performance also seemed to vary within the beta [so I'm only trying to suggest that they were testing different performance levels, possibly]. It's extremely fun and natural to get into, with a strong degree of challenge and teamwork. For me it's like a multi player beat em up that is accessible and can alternate between players who want more variety/depth/play styles or more casual players who just want to get in and get out [like me].
It's fun for what it is: a fantasy multiplayer co-op action game. It is not Fable 4 nor does it have much RPG trappings. If you go in wishing it was those things, you will be disappointed and annoyed no matter how fun the game actually might be.