I realize planar adventures will be the last Pathfinder hardcover so I'm really excited for it. I also had a sweet idea for something I'd love to see: Etraplanar beast companions as alternatives for rangers, hunters, druids, etc, possibly associated with planar archetypes for those classes.
This may be a little zainy and out there but I'd love to be able to team up with some kind of shadow hound or ethereal bat or phase shifting beetle. Maybe they could be more intelligent than proper animals or vermin from our plane and have supernatural or magic abilities allowing for a more subtle play style than "POUNCE!"
*bump*
This might go over better in the Pathfinder Compatible area. At this point, I expect Paizo to be wrapping up creation of new material for Pathfinder 1e.
Sad but probably true
Maybe a X-level gunslinger with Pilot +20 (Millenium Falcon)... and a Wookiee companion.
There will be some cool options in it. Back in the day, the Manual of the Planes was one of my favorite books.