So EA is just Act 1 (out of 3?), which had a surprising amount of content, probably 40-50 hours, but I do everything and play slow. With that being said, not all Act 1 content is there in EA. Some areas are locked behind invisible walls for instance. Additionally, not all of the content that is availble to play in EA is content complete. They said they held some things back so that people who have played EA thoroughly have some new experiences.
While they have not come out and said it yet - it is widely expected that all classes and races (except for Artificier?) will be playable in the game. I think the only class that has not been released yet is monk, and half-orc and dragonborn have not been released yet for race.