If you look at the world, certain races already have roles that each one falls into.

Thaumaturges tend to be Lalafell (dunes folk)
Lancers tend to be Elezen (both duskwight/wildwood)
Archers tend to be Miqo'te (both seeker/keeper)
Conjurers tend to be Hyur (midlander)
Pugilists tend to be Hyur (highlander)
Gladiators tend to be Roegadyn (hellsguard)
Marauders tend to be Roegadyn (sea wolf)
Arcanists are a mixed bag, usually Lalafell (plainsfolk), Miqo'te (seeker), or Hyur (midlander)

These are due to the lore coupled with regional differences and common-sense stuff (Lalafell gravitate towards magic to make up for lack of strength, Roe size and strength gives them an edge tanking, etc.)