Well, flight paths have the tradeoff of taking fixed routes, no arbitrary point-to-point, so they’re a bit different. You also need to visit them before you can use them, which in most cases ensures that the player has explored the surrounding terrain to some extent.
I don’t particularly care either way for flight. It’s nice but if I’m being honest I forget I even have it half the time. It just doesn’t change the gameplay experience that much.
I do think its speed is a little ridiculous though, relative to how tiny modern xpac zones are. The speed became as high as it did back in WotLK when we had massive zones like Dragonblight, Storm Peaks, and Icecrown and made more sense back then. That cat’s out of the bag though, there’s no way they’re going to be able to reduce flight speeds. It’d make me happy if they returned to Northrend sized xpac continents though, which I think is a real possibility.
If flight were to be available right out of the gate, I don’t think it should be gold only. Encourages token sales too much. Put it on a vendor that takes a BoP xpac currency that’s earned by doing literally anything (questing, M+, raids, BGs, whatever). That way the players getting flight first are those who’d make the most/best use of it.