It's hard to name a single fighter that lack clones, so there's literally nothing you can do to expect them to be absent. Smash had been receiving clones (both of the semi and full variety for all five games) since the beginning. It can be for various reasons than juts padding out the roster like just having a certain playstyle with certain variations in case not that many people would enjoy the original. There are some people that prefer Fox's balanced playstyle while others might enjoy Falco's more aerial (referring to his great jumping and slightly heavier weight), thus getting the best of both worlds. People might be more drawn towards the latter (before his unfortunate nerfed this generation) since he's pretty competent in tournaments.
Another great example are the number of Ryu clones in the latter editions of Street Fighter (Ryu, Ken, Evil Ryu, Oni, Dan, Gouken, and Akuma) with their own drawbacks and strengths to separate them from one another. Ryu and Ken are fairly balanced characters that were known for being average while Akuma and Evil Ryu are powerhouses that are rather high in the competitive tier lists. Dan is a pretty low tier character in tournaments, but he's a fan favorite for his quirky personality and interesting attacks. Which also goes into another reason in which that a person might enjoy the clone compared to the original due to how interesting they are as a person.
Overall the most fighting game developers don't add clones for the sake of padding, but for reasons in regards to how the players might perceive them or their differnet playstyles.