I think all they really need do going forward is plan quest clusters for the MSQ where you have 1-2 important to the story and 5-8 filler that is part of the MSQ..with the intention to make those filler into optional side quests once the content gets old.

The moogle section in HW is a good example where you could do 1-2 errands for them and get the idea without slogging through it.

Also I wouldn't be opposed if they just didn't go so nuts on the XP rewards, or made ALL MSQ level-independent (or something like 2.0 is anything under 50; 3.0 anything 50-60). An alt of mine is almost 70 ONLY doing MSQ, just finishing Heavansward and a few random roulettes.. would rather finish a quest but collect rewards on an second job so slow that down a bit.