See, DLC has to sell, so to overturn an objective measure of "who will sell," aka popularity, the team would need a darn good reason to do so (such as that character being owned by a third party or being Ridley levels of difficult to develop). If a character has none of those obstacles, odds are they won't get snubbed just based on developer preferences. Heck, as much as Sakurai's bias gets (rightly) questioned, he hasn't added "the character he wanted most in Smash 2" even fourteen years later (Mach Rider) nor his favorite Fire Emblem lord in Nabarl (or however you spell it).