Well, Zamii did say in the post before that he meant for some fights.

The fights you can confidently stay in the rear (which are fewer, but it happens) then you can have a gear set with less accuracy (like how people have low ACC sets for primals).
Obviously, you can default to a flank set when the fight doesn't allow for that.

He's not saying that you should always just be using the rear cap. He's saying the design allows for a disparity in dps depending on fight design that may not be intentional.
It's kind of like how BRD's dps is gimped when there's not much movement compared to the rest, while it can be more equal now that they have Wanderer's Minuet.

Not sure the acc difference is as significant though, and everyone's dps (except BRD) increases on stationary fights as well.
A fight where you can stay in the rear the whole time is probably the same as one where the MNK can keep up GL3. Dropping acc a little isn't equal to that really.

That said, I think there is a point, that is generally valid, moving forward.
I think positionals and casting are a good base for keeping balance, and gives the developers more freedom with fight designs.
The Job differences should be in the skills and how they work, which is much easier to adjust and build from.