I must admit, the biggest problem I have with Sona's rework is her E.
When ranking it up, you gain 1% on the self movement speed and 1% on allies.
That has to be the *worst rank up gain* in the entire game. There is absolutely zero satisfaction to ranking the ability. Just look at Karma's E. It's a shield AND the movespeed buff adds 5% per rank. The movespeed scaling alone is way better than Sona's which is an ability solely focussed on movespeed.
Also the ability itself is still awful unless you have tons of AP. Why on earth was its cooldown increased even more? It now has twice the cooldown of the original E and so as a whole the ability actually manages to be worse. And it was already bad.
Suggestion: Increase the numbers to 18/21/24/27/30% for self MS and 12/14/16/18/20% on allies. Lower the AP ratio.
With a 12 second cooldown make the ability *actually* good. And a little more satisfying to rank up. Like, give the Sona player an actual incentive to max it second or something.
The rest of the rework I like.