So, what is the hold up on Beastmaster?

[Winterfang]

Then it still runs into the same problem listed, you'd have to know certain spells or you'd get kicked from parties instantly.

I double checked and literally nothing is stopping me from going into Aglaia and Pandaemonium Normal without a job stone, meaning I'm missing crucial abilities. I don't think people are going to be as kick happy some bring up, given how the playerbase STILLcoddles high level Sylphie, even up to Endwalker dungeons.
Now, when it comes to something like Extremes, Savages, Ults, and whatever you would classify as stuff with BA/DRs/ and other such content, then yeah some foresight on appropriate spells should be a given. But that is higher end content so it should be a given that if you want to take a job like that into such difficulty, then additional prep time for learning spells is not a heavy price to pay, especially when you're going to be capped at that point and can go back and easily learn spells you potentially missed.