Honestly, as long as both racial languages and Common are a thing, Human should be a distinct language from Common anyway. Common as the de facto Human language, which pretty much everyone else conveniently speaks, feels...odd. It paints humans as the default that everyone else bends toward, and takes away one of the few possible points of distinction that could make humans feel distinct from other peoples: as is, there's basically nothing that's unique to humans.
Divorced from being synonymous with a racial language, Common would come across more like a pidgin language, or something along those lines: a simplified conglomeration of a number of different languages that lets everyone convey basic concepts to each other - if not complex, philosophical debate or the like. It wouldn't be strictly necessary to share a non-Common language to be able to converse or negotiate under that paradigm, but it would certainly help grease the wheels a bit.
(This is only tangentially related, at best, to what classes do or don't suck, but humans not having their own language when every other core species does is a long-standing pet peeve of mine.)