My take, for what it's worth, on priorities for those attractions that now offer FP/FP+. Original list reflects reported current options only and is courtesy poster
Vertical:
FP+ Attraction List
Ranking System:
A - A must-get or risk waits of an hour or more.
B - Take it or leave it. Might make sense, depending on circumstances.
C - Chump. Rarely makes sense to get, but can also depend on circumstances.
*
Attractions listed within the same priority group are in alphabetical order and not meant to suggest priority within the group.
MAGIC KINGDOM
A - Big Thunder Mountain Railroad
A - Enchanted Tales With Belle
A - Peter Pan's Flight
A - Space Mountain
A - Splash Mountain
B - Buzz Lightyear Space Ranger Spin
B - Haunted Mansion
B - Jungle Cruise
B - Main Street Electrical Parade *
Does not always appear as an option
B - Meet Ariel at her Grotto
B - Meet the Disney Princesses at Town Square Theater
B - Pirates of the Caribbean
B - The Barnstormer
B - The Many Adventures of Winnie The Pooh
B - Tomorrowland Speedway
B - Under the Sea - Journey of the Little Mermaid
C - Celebrate a Dream Come True Parade *
Does not always appear as an option
C - Dumbo the Flying Elephant
C - Mad Tea Party
C - Meet Mickey Mouse at Town Square Theater
C - Mickey's PhilharMagic
C - Monsters, Inc. Laugh Floor
C - The Magic Carpets of Aladdin
C - Wishes *
Does not always appear as an option
EPCOT
A - Soarin
A - Test Track
B - Maelstrom
B - Mission: Space
B - Turtle Talk With Crush
C - Captain EO
C - Illuminations: Reflections of Earth *
Does not always appear as an option
C - Journey Into Imagination With Figment
C - Living with the Land
C - Meet Disney Pals at the Epcot Character Spot
C - Spaceship Earth
C - The Seas with Nemo & Friends
HOLLYWOOD STUDIOS
A - Fantasmic *
Does not always appear as an option
A - Rock 'n' Roller Coaster
A - The Twilight Zone Tower of Terror
A - Toy Story Midway Mania
B - Star Tours
B - The Great Movie Ride
C - American Idol
C - Beauty and the Beast - Live on Stage
C - Disney Junior - Live on Stage
C - Indiana Jones Epic Stunt Spectacular
C - Lights, Motors, Action! Extreme Stunt Show
C - Muppet Vision 3D
C - Voyage of the Little Mermaid
ANIMAL KINGDOM
A - Expedition Everest
A - Kali River Rapids
A - Kilimanjaro Safaris
B - DINOSAUR
B - Festival of the Lion King
B - Finding Nemo
B - Primeval Whirl
C - It's Tough to be a Bug
C - Meet Favorite Disney Pals at Adventurers Outpost