I think people wanted something like M+ from wow which is really popular but variant and crieterion isn't that. V/C is all bosses the bosses have puzzle mechanics where its not obvious what is going on to someone that is watching the game, most people rely on videos to do these after the puzzle has been solved by other players that are good at puzzle solving. V/C difficulty comes from executing the puzzle correctly and less on dps/healing/tanking. M+ however all the bosses have very simple mechanics you can figure out what to do just by playing the game no need to watch a video or guide to figure it out the difficulty comes from higher boss hp and damage. So you have harder and harder dps/healing checks and they have a timer in order to get a higher keystone to do i higher level dungeon you have to beat the timer.
I would personally like it if FF14 had something else for difficulty besides puzzle bosses. Take the regular dungeons and start to scale up those bosses and mobs with more HP and damage taken.
