Unless the tank stance is literally 100% accuracy their will still be disparity in accuracy needs between front and sides.
Tank gear needs to have some accuracy almost like a gauge, otherwise you could just get accuracy-less crafted gear and overmeld it with pure tank stats and be relatively way too strong
throw in accuracy needs and all of a sudden the higher level tank gear becomes necessary for threat management, having a built in boost just lets you divert some of those stats to more tank oriented ones
Healers on the other hand are meant to heal with the vast majority of their time but they also have some debuffs and moments where doing damage as best they can might be necessary.
It just makes sense for healer offensive spells to have a built in never miss for mechanics sake, honestly doesn't even need to be tied to cleric stance
the only one that this would even cause issues for is scholar since they share skills with a dps yet somehow they're the one that already has it