I've been levelling some new jobs, and have repeatedly run up against the new system for accuracy. I don't know if in HW or ARR we just were always able to meet acc check for mobs, however since Stormblood it is not consistently possible to do Leves after popping up the difficulty a notch simply due to the non-negotiable debuff of randomly missing on higher level mobs.
If this is still completely intentional, then I would like to posit that instances where we are forced to fight higher level mobs by design likely are not. In particular (because it nearly drove me insane...) The "Hero on the Halfshell" guildhest, in which both the turtle and the fire sprite are level 17, but all party members are level-synced to 16. I missed on that fire sprite 6 times, and it dragged out that guildhest way longer. It's embarrassing that simply due to luck the paladin had to come over and kill it because the new system decided to RNG me into being completely ineffectual against the enemy.