Thats because many of the armors are for specific classes. I have a nightborne hunter but the heritage armor is a mage/spellcaster armor, it looks stupid on a hunter. Same with lightforged Draenai, that screems paladin armor.
Aside from that i like the allied races, i leveled 3 to 120 and one is lv 104. I like leveling and the races give me a reason to do so.