I agree with Koltik's point.

In addition to that, I see sprint as an ability to fix positioning mistakes. I don't have sprint on any of my profiles and here is why:
Not having sprint forces you to actually think tactically about your positioning. If you have to use sprint to secure a kill, or to get away from a group of enemies, you're relying on that ability too much. Sprint isn't going to save you from a RDPS who out-positions you or a tank who stuns when you're about run away—doesn't really help against good healer juke either. Even MDPS who are, in my opinion, hardest to position well without sprint, don't need it. SAM, NIN, and DRG all have ways to retreat and/or gap close without it. MNK being the only one with no true means of retreat out of a pile of enemies.

Calling sprint a necessity is silly and making it a native ability would be pointless.. Previous point aside, if everyone had sprint, I'd just save mine to counter the opponent's. So why have it at all?

In addition, I believe making sprint native would be counterintuitive for SE considering their reasoning behind the PvP changes was ability bloat and balancing.

TLDR: Sprint has a 45s CD. Positioning doesn't.