You're missing the key here, without the former (jumping) they wont create the latter (new elements of exploration). thats like saying, . They wont make the NPCs walk around if there's no NPCs. they have to have NPCs first. same concept.
Basically, jumping and extra content for it can be either released seperately or together. point is, you would rather have the jumping released first. because releasing content for jumping before you release jumping, is sorta. ya know. wasting time, as noone gets to enjoy it.
