I wish that Blizzard instead of Allied Races as they exist now, had created some kind of sub-races (just called differently) system, as imagined at the time by many in the community.
For example, Humans being able to choose between Stormwind and Kul'Tiras at creation, same goes for Troll tribes, Dwarven clans, etc. This would have allowed a much smoother addition of races such as the Lightforged, which to me are so redundant of the draenei (yet I absolutely adore their customisations) or Highmountain Taurens, Mag'har Orcs, etc.
More "unique" races not falling under such categories such as Vulpera, Nightborne, etc. could have been introduced as either normal races or allied races as they are now. This would have added a lot to the immersion, for example choosing your clan as you create a Dwarf character (allowing for the Wildhammer to truly exist instead of just adding feather customisations to Ironforge dwarves) or an Orc one.
I think the allied races concept and split could have been done in a much smarter way, at least in the way the interface is created, allowing for even further customisation in the future and a less "heavy" interface.
