Back in the days of sky and sea, you'd usually be mage heavy because melee could barely hit and/or do any damage to sky/sea gods. Sky gods would mess melee up with their 2-hrs when someone doesn't turn for shadowbind on Seiryu. Every TP move and spell from JoH or JoL would mess up any melee besides plds close to the mob, so a "run in and SC +MB" mentality was both effective damage-wise, and safe practice (rngs were also used by my shells). This mentality lost focus in experience parties when ToAU and birds camps came out, but remained for endgame of the generation, such as ZNM (sara/tinnin, level). Level cap increase came, sky mobs could be hit, hurt, and broken by higher level players. This goes for sea, as well. If SE wants SC + MB to come back in full force, they'd release endgame content to where the big bosses can hardly be hit, hardly be physically damaged, and can one-shot swarms of melee every TP move like olden days. I understand VW bosses do that now, but those don't really count when everyone is given fanatic drinks or whatnot after every proct. This is my personal history of xp parties and endgame tactics throughout the years I've lived in Vana'diel. I personally love SCing and MBing (hence I leveled sam and blm mains), but like everyone says, against mobs that don't have ridiculous eva/def/pdt, coordinating SCs + MBs have no place currently.
Oh, and I'd LOVE it if SE added Cosmic Elucidation as a higher tier SC.