The more I play FF Explorers anyway, the more I see trinity system being way more efficient than everyone being hybrid. A real tank on some of those bosses is so very helpful (shoutouts to my lv50 Black Knight monster buddy) and some eidolons have really nasty moves that are almost impossible to dodge if they're focusing you and extremely damaging to cloth-users ('ucking Fenrir clone multicharges). Not to mention if a monster keeps bouncing around it's impossible to hit specific body parts for breaks. Sure everyone can equip Cure/Esuna and hybridize to a degree but that's a significant chunk of your ability allotment which could be used towards higher echelon abilities within your specialty.

It's very much like FFXI except for the having easy-mode for solo, hard-mode for multiplayer part and less gear-dependent. Not sure the option to hybridize a bit would do anything for FFXIV except open up cross-class skills to being more nerfed than they are now.