One of the biggest problems with the "just stay behind the boss and hit buttons, don't worry about positionals" argument is that conflicts with another problem that some melee job players seem to think should also be "fixed", and that's "The boss sometimes does things that make me run away and I can't hit them!"

Removing positionals from the game means that SE's only real means of controlling melee players will be increasingly more elaborate AoEs, which will also negatively affect jobs with cast times, and honestly I think that will result is less interesting encounter design. One of the reasons I don't care too much about trying to do Savage/Ultimate is I simply do not have the time or willingness to learn what amounts to an arbitrary interpretive dance. It doesn't look fun, visually it's a mess that my increasingly older eyes just can't keep up with. But the endpoint for the removal positionals will be to bring that sort of design to standard content in order to provide challenge.

That might not bother me too much in the end, because it would be balanced for the rest of us. But given that there's been a rash of players complaining about needing to stay in MELEE RANGE as their MELEE JOBS, removing positionals will ultimately have solved nothing for people who don't want to be asked by the game to do anything in any specific way.