I wish Square would give us the option to start the new classes at level 1

[GTK0HLK]

Sadly it cannot be, The game has existed too long for it to change now.

SE had chosen the path of least work.
So there is no deep or intricate Role/Job/Class Quests for the newer Combat Roles.
There is less reason for them to go back and make Weapons for new combat classes in old expansions.(which I bet they love having that as another drop in the bucket of reasons why they don't want to go back and make New Relic/Ult/Trial/Raid Weapons for New Combat Jobs in old content. as much as I'd love New Zetas - this isnt a joke, Zeta is worth it. But not on alt characters-<says the full zeta>)
There is also even less they have to worry about with the jobs being entertaining at lower levels, as most will have most their kit at higher levels.(so intended or not, the lack/scarcity of abilities as lower roulettes gets worse.)

People Love Leveling, no ones got the right to deny or argue against anothers preferences in what they enjoy.(if they treat it as subjective. Since it's a For all game.)

Though I get how some may love playing with the new toys day 0, and only require to level 10 times.

Telling them to make their own content is utterbull by saying to purposefully queue in old content.
(unrelated kind of/adjacent. But Leveling in itself is part of the games enjoyment. if it was not, everything would be Capped.)
It's like many forget how people feel about the lack of content/increase in boredom as of late. and peoples view on some making alt characters.

Regardless, game has existed for way too long.
It exists how it is, and it won't change OP.
(Even though one can find many subjective and objectives. Like Side effects of increase in queues being more even spread, rather than top heavy as more expansions release. as just one)
[if it was a new MMO, probably wouldn't hurt if it all started at 0-1. If so, then boosts also would be pretty evenly valued to all jobs, regardless of how you view boosts.]

TLDR:
It's far too late for XIV to even consider that, even if it has its merits(which many don't want to even consider, for also good or bad reasons)

[But I would whole Heartedly Support it, if they also adjusted and added more to the game, outside of just increased Leveling. Optional is always there for sure. But it will always be a you have no choice regardless]