Does it bother anyone else that SE assumes we're going to buy heavensward?

[Tyrial]

Theres a big difference between WoW and XIV though in the fact that wow tells it's story through its raids.

XIV story is just that, the story. The end game raid doesn't tie in to that.

If XIV was like WoW, we would be beat t13 and that would've been the end of the ARR story and the end of HW story would be us beating Alexander.

That's not entirely true. Coil had it's own independent story but it tied into the Main Scenario beginning with the ending credits for ARR after you clear the last story dungeon for 2.0. They've deviated from that for Heavensward because the "Story" (if you want to call it that) has been linked to the easy mode raid as opposed to the actual End Game raiding.