I want to point out that saying that jobs shouldn't start at level 1 for reasons that going from 1 to 30 (or 1 to 50) is a long and boring experience... it's an irrelevant point to bring up because time investment is tentative. To give a simplified example, let's say going from 30 to 70 requires 100,000 experience points. Now let's say going from 1 to 70 requires 100,000 experience. See what's being said here? The exp curve can always be adjusted so that the time investment remains roughly the same regardless of starting level. However, only one of these options gives the feeling of truly leveling your character from the ground up.

There is also the rule that "new jobs should start at 30 because all jobs start at 30." That is another point that could very well become irrelevant with their plans to eventually dissolve the class system in 5.0. That's going to mean either every single player starting the game will immediately jump to level 30, which I would rather not see, or we're going to start seeing jobs start at level 1.

Speaking truthfully, I think the real reason we saw Heavensward jobs start at level 30 was because they didn't want to take the time developing quests for those jobs from level 1 to 30 which would be expected. However, technically speaking they could still start at level 1 and SE could choose to not write quests anyway. Similar to how, despite progressing through level 50 as a new job, no quests were written for players to obtain their first set of signature job-specific armor, nor were the armor sets created at all for level 50. So while it is true that people would probably be annoyed by the lack of story content for these new jobs, that in itself isn't enough to justify completely skipping those levels when it isn't a necessity for them to create those quests regardless.

So these are just some logical counterpoints to foreseeable arguments against having jobs start at level 1. I have always been in favor of having the newer, class-less jobs start at level 1 because I consider it to be the proper way to grow your character.