Okay everyone, focus.

[Welsper59]

OK... all the people that say "It's not that bad" or "It's useful"
If they added Dancer... and also added any other class that did the exact same thing (Had abilities that buffed or healed the party using TP).... then people would opt for the alternative class in a heartbeat
If it was a geomancer or atherist or something like that, and it used the energy of the planet to cast haste or heal the party... people would choose that over Dancer almost every time...

Honestly, if FFXI didn't already introduce the DNC to a FF MMO, I'd probably go with DNC over Geomancer (though a GEO would be awesome to have regardless). The concept of dances doing what they do is far more intriguing and unique compared to the concept of some mage utilizing the elements to do their bidding (almost like a BLM/WHM would to do their roles, or that every magic-based fantasy book/movie already has). That having been said, I'd probably now go with a Geomancer more than Dancer primarily because it hasn't been done yet in an FF MMO. No other significant reason, assuming they were to fulfill the EXACT duties and spells, just different animation.

The idea of a Bard, referring to your earlier comments, is actually enlightening. Believe it or not, as obvious as it may be, there are people out there who play instruments. The idea of something found in the real world, especially if you yourself can play or appreciate music/instruments, having magical powers in the game, can be attractive. This pertains not just to Bards playing music, but even to Dancers dancing... and anything else found in a fictional game.

Plus there's the comedic value to consider. Have FUN with a game, don't take it seriously. Think about the first time you saw the dance steps (especially from a lumbering tower of manmeat like a galka), you most likely got a chuckle out of it if you aren't one of those "serious business" type of people. Even NPCs in FFXI made fun of the Galka dancing in Jeuno. It's a concept that shouldn't be taken seriously... I mean it is a video game, despite what some may think. This just brings up the whole argument aesthetic items being introduced (like the Goobbue mount) ruining the game, claiming it breaks immersion or destroys value of the strength monsters have. Like they have to make it their lifes mission to make sure a video games fictional universe is as close to "real" as possible.

Games don't have to be serious. Games don't only have to be about "cool" sword-wielding, heavy armor wearing, muscular, sweaty men... nor does it have to only be about flashy magic spells that make things go boom. Games have to be about "Fun". An online game, specifically MMOs, have to cater to the extremely diverse definition of "fun". People need to understand that what you want, may not be what others want... and even moreso, it may not be what the developers have in mind of what's "fun". We're human beings in the real world, we have the capability to adapt our minds... hence an imagination. Learn to utilize the skill to adapt, and you might find what you enjoy can be even more enjoyable than you thought.

tl;dr : Go outside.