It would be like if instead of putting Dr.Mario, Pichu, and Roy in Melee, they put in Wing Cap Mario, Metapod and some generic enemy soldier from Fire Emblem. Or instead of putting ROB and Wolf in Brawl, they put in a playable Powerglove and the train conductor from Macbeth. It's one thing to have minor unrequested characters, but at least make sure they're somewhat deserving before you do.
No. It'd actually be more like; If in the original Smash Bros, instead of Including Luigi, Ness, Captain Falcon, and Jiggly Puff (i might be confusing those last two secret characters, it's been years. sue me) they added Kirby (whether they'd keep him in as a standalone or not) with the appropriate hats.
3 Rabbids? Really? ugh.