If you want to optimize you always need to go human, sub is physical dmg which makes it more gear dependent than most. Having that extra trinket which bis would be DBW/WFS/DV and all situational stuff would help you a lot. Having that extra trinket let's say it's DBW, you are able to equip more pvp gear than a non human could equip meaning you have more survivability than a person that wouldn't be human and does that damage. DBW gives a good amount of ARP and with the right proc you have an insane amount of atk power *cough* 10k *cough*, all from the comfort of having 900-1000 resil in 2s
That being said if you like to outplay people more, go night elf the extra vanish makes for some fun plays.
EDIT: Also the % to miss on you is frustrating it doesn't matter how much hit they have, I can't count the times a vital ability like blind/kidney or just a damn ambush or cheap misses on nelfs.
The belf racial isn't really that situational, you can use it to mask a kidney on a paladin so he can't freedom without having to garrote it, interrupt ppl around you with kick on CD, or just use it in shadow dance to even get more energy back over your 5 cp finisher +25 energy returns from relentless strikes which in turn = more abilities in shadowdance = more dmg.
Orc is also a good choice because of the extra atk power you can macro it to doing shadow dance, tho it's a 2m cd so you won't always have it. Also stun reduction for RvR
Undead is swag points + the 45 sec cd if you get feared instead of 2 min, plus you can disrespect people by eating their corpse when they don't release.
Dwarf can use his racial to avoid bleeds when vanishing which is also nice in some situations.
Just pick whatever you like tbh, just get good at the class and the race won't matter that much I switch all the time for the lolz