Not without some significant changes to melee job kits.

One of the things FFXIV has to contend with, with its highly scripted battles, is the threat of becoming a "rhythm game". That is to say, once the mechanics of a fight are learned, the game should still be more interesting than just pressing a sequence of buttons.

Machinist suffers from this - it has no positional or movement concerns to worry about, and its rotation is a fairly exact 60s script, so once you learn the job any fight that's not mechanically unfamiliar is going to be quite boring to a lot of folk. All you do is press your buttons in order.

Bard is made interesting by demanding that the player manage procs, DoTs, a song cycle, MP, party buff snapshotting, etc. This is all to make up for its lack of fundamental concerns. With casters, it's optimizing movement and also some proc/priority stuff in their kits that creates replayability; with healers it's cast times plus juggling survival and dps; with tanks defensive cooldowns and melee range.

Melee have generally well-determined skill usage - little about their timings or sequencing is random or heavy on priority management - but their gameplay is spiced up by the need to not only be in melee range but also hit some positionals.

Absent positionals playing melee would get very snoozy once familiar with a fight, as we've seen in complaints about O6S. There would need to be a big re-think on melee kit design in order to be able to shed positionals without introducing this problem.