ES is instant cast and takes hardly any mana. Just isn't needed. Also, who even heals 5 mans as Resto? I haven't healed a 5 man in Resto spec since a few weeks after MSV came out. Ele can do all the healing you need for 5 mans.
I'm a Dwarf, so the size part doesn't bother me, but I completely agree that the current Ascendance sucks. Should have made Ascendance look like our Primal Elementals instead, with a water version for Resto.