I'm DNC, WAR, BLM, RDM, BST, SMN, (and level 82 BRD and 75 RNG)

The things I choose to do just happen to generate xp. I capped my merits for all of my jobs (including re-meritting things) while I was level 80 just doing things like farming Dark Rings or skilling up. It's not hard to cap merits when NMs drop 5k xp and normal monsters net 1k xp per kill (including Ops).

If it's a priority thing that's fine, but 5 Berserk and 5 DA is what you would do if you wanted to be the best.