I agree, common should not exist. There should be distinct human languages by region, some regions very, very small and none of them should be free to non-humans.
In most settings there is... greyhawk had suloise for example. Common was originally the trade language everyone spoke to facilitate trade, like English, a mutt of languages that facilitated communication.
Wicked Fantasy (A 3rd party book for pathfinder) did a revamp on all the core races including Humans which were revamped and redesigned to show off their edge amongst the other races. They tried very hard to make humans unique and interesting.
Other than this one instance I agree its pretty lame that humans are the boring race.
Never played greyhawk. Most of the big settings like FR actually dont though. I think Eberron does, but it also has common. I'd like to see common disappear. or be replaced by lots of little regional "commons" that are local trade languages.
Before I get worked up about racial languages, I'd like to see good rules for languages, period.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.