Ultimately yes, it comes down the linearity of the game and the design behind the zones as well as the gameplay. Really at this point I think it'd be better to start a crusade for more open zones either alongside or before demanding a jump feature. What good is jump if you're standing around in a prairie right?
Anyways, some types of games benefit from certain features more than others. They provide different experiences. To say one experience trumps any other and trying to back it up logically is pointless since it's all a matter of what people enjoy the most personally.
I can't argue that your idea of a fun, engrossing mmo is wrong. That is a purely opinionated discussion. So really at this point it might not be as beneficial to argue why jumping should be implemented and more so to gather support for a more open style of play. Because really, at this point, we've come to the bottom of the argument, the fundamental disparity in our views. It all boils down to what kind of game we want to play and what features we think deserve the most attention. Though XIV isn't a very welcoming environment to jumping, if you're willing to build support for changing that then go for it. The changes it would undergo probably wouldn't greatly appeal to me but I have no reason to say that my idea of fun is any better than your own. It really just matters what the most people want in the end. =/
XIV is a specific type of experience, one that doesn't cater to everyone. However, if enough people demand it there's potential to change it so fundamentally as to steer it in an entirely new direction leaving it nothing like what it is now. It's a tall order but if the people demand it then so be it.
I feel a need to summarize what I'm saying in like... two or three sentences. Essentially, XIV isn't a jumping man's game and wasn't intended to be, it gives an experience apart from other mmos. If you're up for the challenge though, and if SE agrees with you, you can possibly change it into an entirely new game. We aren't really dealing with why jump would or wouldn't fit into XIV anymore, but if XIV should be the kind of game that it can fit into.