actually is true and false, we already know that a few jobs are here for only do massive dps, like blm and sam. for me i think the DNC will be the job that will support this sort of dps that have technically no buff and are only here for dish a tons of dps...
even mnk can become a monster, let see.... dnc with saber dance with a mnk as buffed allied... the damage that the monk will throws will not be small and i think that them goal.
right now the goal is to add buff over buff over buff... that why job like brd/drg/nin get place in raid while having far less potent dps than the high dps job... but we can't be sure without get the whole picture.
because it's important to remember that brd do loose the +2% crit on song, that the reduction of resistance is out too.... a lot of important buff will disappear, how it will be translate in the dps of the jobs that did loose some of this effect is something we don't know... maybe bard will get a far more potent dps.... who know.
for the DNC it will depend on which job you will choose as dance partner... saber dance add 30% of critical and dh.... what is cool but have a huge cd, some job will become monster with this buff, other less but still get strong.
it will depend of what the team have as dps, if they have a monk, samurai or black mage a dancer will become really strong for buff this one. the synergy between monk and dancer risk to be really high, since the dance partner can give ressource to the dnc allowing it to use better skill and dance.
then why the monk will be really good... because the monk will be the fastest attacking job of the game... means more attack = more ressource for the dnc...
all in all it will be like a group into the group. a duo that have for sole purpose to deal insane amount of dps... do it will be mandatory, not really actually. drg and nin still have potent buff and can be interesting as buffing jobs... but like i have said we lack the whole picture... all we can do is theorize on air since we have not the whole change that the job have get or the new skill....