Would lore influence what race you play? Yes, but it's not the most improtnat factor, it certainly decides who I don't play.
What sub-race you would pick (if they become available): Yes, I would not play Zandalari if they became avail
what Class you choose: Yes, I loved Mage, Druid and Hunter in lore, hated Warlocks. I would instantly roll a Broken Rogue if the sub-race became avaail.
What faction you pick: at first yes, now no. It does influence what faction I like though
What Areas you quest in: without a doubt.
Whether you keep playing wow: not really, lore is turning me off the game, it's really rubbish compared to Wc3 days