It seems to me like the stance dancing is there to paper over the fact that the act of tanking in this game is A) very simple and B) not particularly ... tank-y.
My interpretation of what a "tank" is supposed to do comes down to keeping the target's attention away from the rest of the party and staying alive. This is the tank jobs' purpose in FF14 as well, but unfortunately neither of those two things provides much of a challenge. Enmity is borderline a non-factor and so long as you follow the mechanics of the fight like everyone else, you shouldn't have trouble staying alive, either.

So with the two major aspects of tanking out of the picture, what does your gameplay focus on? DPS
Hence why staying in tank stance feels so bad for so many people - the tank stance's contribution to your survivabiltiy and enmity output is largely unnecessary while kneecapping the DPS you contribute to the raid.

IMO the best way to go would be to cut the stances altogether and shift the tanks' gameplay more towards mitigation. DPS should only be a by-product of the tanking gameplay, secondary in concern to minimizing and smoothing your damage taken.