I think it's fine this way, there is enough wiggle room to give you a little edge in the things you want. Bringing back the WHM example, I went with 15 in INT, MND, and PIE since I find myself nuking enough even while main healing to warrant increasing my damage/accuracy, and having the Aero/Stone effects land more consistently is very useful. The numbers are high enough to feel the little boost but low enough to not feel like you are gimping yourself if you decide to spread around.