I agree with you. This is simply no single player game that you might enjoy for the story, this is a MMO. They can go and focus on the story more than other MMOs but they should not forget that the most important part of a MMO is the gameplay and the rest of the content. Unlike single player games where you sell complete games, here you need people that pay for it each month to create more. And people will only stay if they have something interesting to do. And like you said, the story is something you only do once. (And some are not even watching it once) I mean each new patch you can go through the story in like 2 hours depending if you have a dungeon/trial in it or not and be done with it for the next three/four months. I really do like a good story (even though some story decision in HW really took me away from it in this game..) but I also know that I would not play and pay for this game at all if the rest was not there.
I really hope that with SB we will have more content that you can put your time in without it being too frustrating. For example in other games fishing is a mini game itself. You need to press certain combinations of letters to succeed and I kinda liked that. At the same time you could also just simply do nothing with the consequence of having a lower chance or worse fish. In FF14 you sit there, have enough equipment, the right bait with you, are there at the right time with the right weather...and yet getting the fish is still so much RNG..that it really does not feel much fun. And having fun is really important.