Jiggs is at more risk, I'll admit. Overshadowed by the more important Pikachu, the actual protagonist Pkmn Trainer, the popular and returning "villain" Mewtwo (who is almost certain due to his recent promotions), and the more popular Lucario and Zoroark, Jiggs' only real merits are its unique moveset and its longtime veteran status. Jiggs was hardly even represented in Brawl by many mains, and was unlocked really late, suggesting she was one of the last additions to the game (meaning Sakurai might have been hesitant). She's also lost nearly all of her relevance and popularity (originally based on the season one anime, which is long gone), since Smash Bros one. If anyone's getting cut from the originals, its definitely her.