I never understood why humans are usually considered as a bad race in DnD games. Being able to have 1 ability to 14, 2 to 16 and 3 to 10 is good enough to me and that is the only race that can do it at level 1.
Sure, it's just about numbers... but humans can be balanced and powerfull characters.
People are boringly predictable in their preferences. The human fighter is by far the most popular combo in D&D, and almost everyone wants to be overpowered. The basic human race is not great, but fulfills the archetypical role as an all-rounder well without excelling at anything. The variant human however is likely one of the very best races and propels the human into being excellent or best at anything which kind of breaks the racial mold in my opinion. They really shouldn't be included in vanilla for balance reasons, unless similarly viable alternatives are made available for non-humans (at which point elven subraces like the Eladrin or Shadar-Kai would make the rest redundant from an optimized perspective).
There's already a mod out that incorporates variant humans and many other "optimized alternatives".
