SCH don't need the extra MP but WHM do. As a WHM, I value mind, spell speed and piety. Once you are stacked with ilvl 90 gears, your mind will be so high that you do not need to worry about it anymore. Having a lot of PIE means faster MP regeneration and less or no dependent on mana songs. Having higher spell speed means faster casting of spells especially stoneskins. But yeah once I get the coveted allagan cane, I will have over 5000 mp so the mp regen will be crazy.