Devs, please make job crystals in lv 31+ content mandatory.

[Azuri]

Being bad at the game is different to actively not using the job stones that gives you access to the actions content post level 30 is designed for. There's a fundamental difference here and even if someone misses every tooltip and help menu as a new player, you just solve that by force equipping the stone therefore meaning they can't miss it.

Does it matter if the end result is the same? I can show up to Copied Factory and spam Ture Thrust on DRG and that's completely fine. But somehow just being an Archer (that does more damage than the lowest DPS in the party) is such an issue?

I don't think allowing classes into casual content is intentional, more like an oversight they're yet to fix because Arcanist has two jobs on a single class. The solution is to simply have one of those classes be a separate job unlock so Arcanist only follows through into one job.

Classes and jobs are a legacy from an era of FFXIV game design that no longer exists. It wouldn't be wasted effort to actually go back and fix this to reflect the modern design of FFXIV. Gladiator might as well be Paladin from level 1 in the same way Marauder might as well be Warrior. It's been almost a decade since ARR, we're way past the stage of jobless gameplay being anywhere close to intended game design.

I'm not sure how is Arcanist relevant to this. As I said, they already have a system that prevents classes from entering certain duties. They could have easily applied it to every duty past level 30. But they didn't. And if you think that completely reworking the very foundation of combat system and a dozen of class quests to remove a working system that doesn't really cause any significant issues is worhtwile... well, Director and Producer himself seems to disagree with you.

Finally, there's so few people that actually want to play jobless as an intentional choice that I don't think the game is hurt by taking that away because in reality you're not actually losing anything.

I'd personally lose and entire power fantasy I enjoy. And have it replaced with one I utterly despise. Pretty big deal, tbh.