In my opinion theming involves a story and ideally approaches some level of immersion. We have always known that there would be signage and other decorations in the queue and station. That isn't the same thing has conveying a story or taking you into a different world.
Before people jump in with sarcastic and snarky comments about BGW not being Disney, in my opinion InvadR (as just one example) achieved that goal.
Regardless of the reasons for the lack of a real story or effort at immersion, BGW has done it in the recent past and has chosen not to for Pantheon.