agreed with DMG.
It's not so much that people prefer everything to be the same, it's the fact that what's different isn't necessarily good. You don't hear complaints about Charizard's nair or Wolf's shine because even though they are different, they are effective. Wolf's nair isn't particularly safe in comparison to Fox or Falco's nair/dair, so it isn't as well qualified for the same purpose. If you could down+b out of Wolf's nair it'd be insanely different, but no one would complain about it being bad anymore!
It really boils down to "comparatively, is this useful". Wolf is a fairly balanced character that is very skill based and has the ability to "flow" very well in many unusual situations. That said, Fox and Falco are not balanced characters in the slightest in that they have ridiculous moves that aren't even close to being rivaled. Fox's nair/dair approach is literally safe in all but a small handful of situations, they're projectiles are easy to use and force approaches (or in Falco's case, allow him to approach as well), Falco's dair is a true spike that is stupid easy to hit with and on its own can hit 3 times if someone misses their first tech, Fox has a super fast u-smash that kills early and a u-air that fits the same purpose aerially...
Wolf is just a well balanced character and Fox and Falco were never brought "down" to his level. He's definitely a solid character, it's just he's so comparable to Fox and Falco in terms of what can be done to him and the likelihood of dying when offstage that you're basically picking varieties of the same fruit. Fox and Falco have legitimate differences between the two that make certain matchups harder or easier, but I don't see Wolf being an advantaged pick in their company.