This isn't anything new, but the new EX fight (last half) really drives the point home about how hard it can be to properly hit your positionals on a melee class. So much so that the only adjustments made to MNK were in regards to more damage for NOT hitting your positionals and a shorter cooldown on True North, because the difference in doing so was much larger. They clearly acknowledged that it was a problem, in fact the addition of True North itself originally should be the obvious example.

From a learning perspective players have to learn their rotations + fight mechanics and then there's the added degree of difficulty with positionals for the fights with the only benefit being you do more dps. With DPS checks being a thing, with the above changes to MNK, and with the design of these recent boss fights it feels like they are basically accepting the fact that you aren't going to hit positionals every time.

To me this is either bad game design or bad boss/es design. You have a skill set that promotes a higher learning curve that separates good players / bad players, then purposefully design fights that take that a step further and say good luck trying to land them OR here is a fight where you can ignore them entirely. That's really what makes me question why they exist.

I would also say the positionals of the boss are still important to learn, so I don't think it should just be a plain targeting circle even if it no longer applies to player's skills. Not getting hit by a cleave cause you are standing in front of it for example. In fact I wouldn't even mind a slight resign to make the flank more distinct if it stays.

There is also the issue when soloing which isn't hugely important given how easy it is, but you are basically stuck with True North or hoping they just so happen to cast long spells while you just so happen to be on your positional gcd. Prior to the TN cooldown change, you didn't exactly get to do it that often and even now 90 seconds isn't exactly a short amount of time. Thankfully everything dies before you can even go through half your rotation anyway so while the point is valid it is kind of moot at the same time.

Additionally I should bring up Eureka and Deep Dungeon. For whatever design reason they thought it was ok for none of these mobs to require positionals. Why is that? The mobs and bosses are effectively the same mechanically if not easier than usual, so why was it worth it to remove them in this case and not throughout the game? Someone put actual thought into it for a reason.

Given the above, I don't think removing positionals would make the those jobs "boring" because:

1) Hard fights are mechanic heavy and either make it nearly impossible to maintain full uptime + positionals anyway OR remove the need for them entirely given the nature of the boss.
2) You don't even effectively use them half the time when soloing.
3) They are removed from content where it doesn't even matter anyway.

The benefit of having them is:

1) Making a job slightly harder / more in-depth to play.
2) Allowing a distinction between bad, good, great players (which I think they were trying to get away from anyway, thus the changes)