It's split up so that the releases after launch continue the main story of the expansion and are included in the price, so no more buying an expansion then having to be playing at a specific time or pay for the follow-up story.
The next part releases tomorrow, so we'll see how that stacks up.
GW2 for the past 11 years, except for a stretch where I played ESO for a few months.
Community's mostly great. Cooperation between players is strongly fostered by the game's design (no kill or resource stealing, no competing for drops, etc), so players tend to get along in almost every PvE situation.
Lore is good, but not nearly as expanded upon as Warcraft's.
Gameplay is what makes it IMO. Skill effects and some gear skins can be a bit obnoxious, especially when you're in large groups for open world and World vs World, but it's still enjoyable. Don't play normal PvP, so can't comment on that.