What even is the purpose of all those non melee/blm jobs?

[Valence]

In theory this would be fine, I'd even support giving ranged physical dps an actual role besides "does low damage for no reason but gives 1% stat increase so we take one" but the gameplay reality would be that you're now making 1 role responsible for your party's success in any content that isn't faceroll.

I don't even trust physical ranged players in my pugs to press their 1 mitigation cooldown consistently, let alone bait mechanics that their role in particular is perfectly designed for (anyone remember bards refusing to do the missle bait during Pantokrator 2 in O11S?).

With mitigation being probably the most important aspect of high end content I do not want to leave all of it in the hands of a single role whose competency then determines whether or not we even get to see enrage.

Are you seriously saying that rphys players are unable to perform properly?