Yes, they're fun to play. This is not Eureka where monsters eat your face and you spend 2 minutes on each enemy. It's facerollingly easy.
The change I explicitly said is to allow players to pick all the classes at level 1. For storyline reasons, Ishgard is all Elezen and not welcoming of strangers, hence you would have to accept a race-lock until MSQ is cleared. SE would have to go back to how 1.0 starting cities worked to change this. Which would allow you to pick jobs that aren't in your starting area, but you can't earn learn the skills until you get to that other area. For Kugane, there's no race-lock, as the city is quite literately neutral area. You can already get SAM at 50, so it would not be locked behind 61 MSQ. Rather you're locked-in until you get to level 15 since Kugane has no low-level field. So the combat tutorial things in 1-15 would take place as instances in Kugane like some job quest stuff does now at 60+.
Progression for everything would be the same. Those who want to immediately get to the end game aren't getting there any faster. But those who want to create new characters or play different classes/jobs as if they were actually complete experiences, would want to play that. Existing AST/DRK/MCH/SAM storylines feel incomplete and don't allow players to start as them. The odd man out here is the red mage, who could have an entire 1-50 storyline as well, but I think it is more sensible to just unlock it as long as WHM/BLM have been leveled to 50. Both SAM and RDM have this "Wandering mystery person" type aesthetic that they're not going to be able to pull off again. If RDM could be started at level 1, what would it be? Magic Fencer?
However the fact remains that SE somehow decided that players would be satisfied with 4 additional DPS, while only adding one tank and one healer since the game has started. So we're overdue for another Tank and Healer. SE doesn't need to introduce all these jobs at once, they can just dole them out one at a time until 5.0 and then 5.0 gives us another race, and other starting class options. Maybe by then they'll have found a solution to this. Or maybe not.
I'm just trying to point out that making the jobs start at some level is the same as going "these jobs aren't important", they're sidequests.