Simply removing classes would be awkward for story reasons. Many of the job stories have npcs from the preceding class stories showing up etc. Hell the SB and SHB paladin stories are more gladiator sequels than paladin stories.

This would make it tricky to actually completely remove, or completely separate, classes form jobs. And also some classes have less of an identity to stand on anyway. Archer just...shoots stuff with a bow and doesn't really have much of an identity. Nor does lancer.

While I agree the class/job system as it is now is a little clunky I don't see an elegant solution and simply removing is probably more trouble than it's worth.

And IMO I'd rather they just continue to add new jobs with no attachment to classes rather than try and revamp the old classes into new jobs. And going back to 1.0 for inspiration would likely just make things confusing since the vast majority of players are not 1.0 vets that would personally appreciate this sort of move.