Overwatch 2 isn’t a separate game it’s a 2.0 update to your current client
The only thing you CAN buy is story and thats optional
As for a roadmap they don’t wanna set a date this would limit ghe amount of updates they can add to the game and im assuming they are revamping events (Jeff talked at blizzcon 2019 about how the Halloween event creator really wanted to redo the event but they had to focus on ow2 I assume the update will revamp events in a big way) also need explained why the events aren’t different is because they’ve been working om this OW2 update since 2017 so once ow2 is out they’ll have complete freedom to change events and they are making story content updating new looks making cinematics writing story making skins for new heroes making new heroes and everything all this takes time
Seasonal events aremt supposed to be a surprise nor is new content Jeff clearly stated last year at blizzcon that they wanna focus on the OW2 update