The only thing that requires planning really is restaurant reservations and booking your place in the theme parks. Even with that, we don't tend to eat in the super popular restaurants (Be Our Guest, Cinderellas Royal Table) so in theory you could just go to the park on a day and get lucky.
Genie requires no forward planning, you buy it and then at 7am, WDW resort guests can book their first ride, non resort guests can start at park opening so staying at WDW does give you perks and benefits. The main difference is
A) You now pay to skip queues
b) There's no guarantee you get to skip the queues for the ride you want. A lot of it is pure luck and rides like Jungle Cruise, Slinky Dog and Peter Pan run out extremely quickly.