"It's been 30/40/50 levels and I still use the exact same skills/abilities/rotation" type of thing is exactly what I'd expect, despite getting bigger stats and gear with bigger stats. It's also a factor of the rework expansions bring. For example, I thought ninja was a lot of fun in Heavensward, but with Stormblood I thought the job was really dull on release day due to the pruning & changes (personally I don't find it much fun at 70 with the changes they made, but that's just me personally). So now someone who starts fresh has to go further to get the final toolkit rather than having them, utilizing them for a year, then adjusting to tweaks and changes, but I'm not sure how you get around that short of the skip potion model.
There's not really a surefire win. Are there any good examples of progression based games where you have every single skill/ability/power up from early on, though? I can't think of one in the RPG genre. Even most action games have you unlock new skills later in the game. Hard to say what the right balance is from the ground up.
Maybe at the very least more off GCD should be introduced earlier. Get your main rotation, some off GCD, then your secondary rotation, some final off GCD, and then at cap you're getting more of your "you're going to need these for hard hitting raid type stuff" abilities or a final notably powerful attack sort of thing.
I'm sure there are classes in game design around this stuff and I certainly haven't taken them.