Jiggs was the "flavor of the month" back then and was at her peak in Melee, Im sorry to say its time for a chance for new Pokemon to be in Smash for representation, especially with 5 generations. Its sad to just leave all those gens with just 1st gen reps (which is reasonable, ex Fire Emblem) but I honestly think its safe to say that the Pokemon version of Kirby is likely to leave...
Also, and I know this will sound kinda stupid, but as an international game do characters considered for Smash really need to have popularity limited to Japan?