Meh there's nothing unusual, only suboptimal.
sub job system would lay the ground work for lots of versatility but SE ruined it with their massive *** for tank, heal and most importantly support jobs. gimping supports when subbed doesn't help the situation either.
the 3 least liked job roles are the most important once. tanks were the only exception on the popularity scale back when NIN tanking was a thing and now with RUN, both times only cause they could also DD. shows how much out of touch SE is with the player base. one would think they finally got the message with COR (support/DD) and RUN (Tank/DD) and i think they even tried with GEO (support/magic DD) but failed miserably.
i think there are exotic setups (or how those setups could be played) but you'd need a group of friends to make it work. shout parties get suspecious quick when you deviate a bit from the norm and most of the time they aren't prepared for it either (for example didn't unlock all WS or BLU's who only farmed the standard DD spells...). ppl also avoid anything that requires coordination as long as there is a alternative, even if it requires massive overgearing and 1hours.