Let me get this straight. K.Rool isn't unique enough to get into Smash Bros., but Young Link is good enough to get in because he has a remake, yet is a 3rd Link, in otherwords something that goes against what you've said here? "able to provide a diverse playstyle from the getgo". Wut? Plus, that whole notion is subjective at best and places you in a very small minority.
Characters are based on source material. Are we supposed to ignore that? Selectively? We referenced Splatoon here and the source material, but we don't mention K.Rool's source material, so he's therefore not unique enough. That just seems strange to me, and frankly unfair.
If we're going to judge characters a certain way, they need to be judged consistently. We also need to cover all bases. Characters don't get in the game because of one thing. For example, if we're going to say that Tharja could get in as DLC because she has a fanbase, we need to add in other factors. Is she unique? (meh) Does she contribute to series balance? (double meh) Does the character make sense? Characters like Geno, Monster Hunter or others I've seen tossed around simply don't meet particular criteria.
Whether you think unique gameplay matters or not is irrelevant. It does. Quite a bit. Sakurai has mentioned it on a frequent basis, and DLC isn't like a group of last minute characters. They have time to work on them. They aren't going to just jam a bunch of clones into the game and call it a day. They COULD do a clone or two. I'm not going to deny it completely. But to go into this thread and say things like, "K.Rool isn't unique enough" and then say "I support Young Link as DLC" contradict one another a lot.