For an Early Access title, Slay the Spire 2 looks pretty feature-rich. What exactly is it 'missing'?

Are they planning to add more Acts? More Characters? Are they thinking about adding in more cards or enemies, or even more events?

From what I've seen, StS2 looks really feature-rich for an EA title. I have seen some placeholder art, but that's literally the only thing I've noticed that would have tipped me off that this was in Early Access.