Yes and no.

Aetherflow is a buff sorta. It gives you the ability to cast certain abilities, ie. your important ones: energy drain, bane, fester(smn), sacred soil(sch), lustrate(sch)....so you want to have your aetherflow active at all times. the mp regen is just a +. I recommend using your aetherflow charges somewhere between right after cast and just before the cooldown is up so your not standing around unarmed so to speak. timing is important especially if you go scholar with the acn