What if; Sona Ultimate rework.

Crazy idea of the day; What if, Sona worked like Udyr? Lose her current ultimate, gain a fourth Melody to perform on a relatively short cooldown. Of course, this would mean that the CDR gained from the ultimate would either be swapped to passive, or removed and her CDs adjusted in consequence.

Here'd be my take on the fourth Melody; This would mean Sona players would finally be able to Peel constantly as supports, for a steep mana price.

Interlude of Motion;

Mana Cost; 80/85/90/95/100 Cooldown; 7 Seconds

On Cast; A wave goes out from Sona in all directions to up to 500 Range, enemies hit by that wave take 30/45/50/65/80 +20% AP and are grounded (No mobility Skills for 1.5 (1? 1 to 1.5?) Seconds.

Aura Effect; Gives a 3 seconds 11/12/13/14/15% +3%per 100 AP Tenacity Buff. Alternatively, could be higher but 1CC only.

Powerchord; Vibrato; Power Chord Stuns it's target for 1.5 (+0.1 per 100 AP) Seconds.

If you have either criticisms or ideas of your own for this type of rework, feel free!