IMHO, I feel Kingdom Hearts is the most likely new label, as the property seems like the most adaptable to an action game as a sale to a kids 6-12 demographic. Sure, Indiana Jones, Muppets, and ESPN seem nice too, but in the end, KH feels like the best action game headlining material. Here's my roster wishlist
Kingdom Hearts
KH1 Playset
Sora
Riku
Kairi
Ansem
Donald
Goofy
KH2 Playset
Roxas
Axel
Namine
Xemnas
Pete
COM Playset
Marluxia
Larxene
/Days Playset
Xion
Saix
BBS Playset
Terra
Aqua
Ventus
I didn't include 3D or KH3 because they are too recent. However, they may have Toy Box characters.
Star Wars
Force Awakens playset
Rey
Kylo Ren
Finn
Poe Dameron
Max Rebo Band playset (pipe dream)
Max Rebo
Sy Snootles
Droopy McCool
Lyn Me
Oola
Figrin D'an
Toy Box
Lando Carlassian
Wicket W. Warwick
Aayla Secura
Marvel
X-Men playset
Cyclops
Wolverine
Gambit
Psylocke
Jean Grey
Beast
Rogue
Quicksilver
Scarlet Witch
Jubilee
Nightcrawler
Magneto
Fantastic Four Playset
Invisible Woman
Mr. Fantastic
The Thing
Human Torch
Silver Surfer
Dr. Doom
Marvel Knights playset
Punisher
Electra
Daredevil
Ghost Rider
Deadpool N' Friends playset
Deadpool
Squirrel Girl
Spider-Ham
Disney Originals
Oswald the Lucky Rabbit (classic Disney shorts)
Gazelle (Zootopia)
The Lion King playset (for introduction to quadruped players)
Simba
Nala
Mufasa
Scar
Kiara
Kovu
Zira
Kion
Gargoyles Playset (pipe dream to ramp up the awesomesauce)
Goliath
Brooklyn
Demona
Jose Carioca (Classic Disney Universe)
Moana (Moana)
The Little Mermaid playset (for introduction to aquatic players)
Ariel
Ursula
King Triton
Goofy (Classic Disney Universe)
Roger Rabbit (Who Framed Roger Rabbit)
For 5.0, we could use Muppets, Indiana Jones (+ more Lucasfilms/arts content), and ESPN together to make up for having spent all three bigger brands, with Walt Disney himself as a figure for the icing on the cake.