With seeing PBE changes, I'm not sure if Ahri will really benefit from changes at all.
1st of all I'm not QQing, I'm just putting my own thoughts after thinking a bit. I'm also a big fan of playing her as a mage and I'm not a fan of DFG, so I don't use it. If you disagree with my thoughts feel free to chat and to discuss it with me :)
From the changes I'm seeing, her W and E got buffed, while the dmg amp if gone. In my opinion this means her poke will be better, but her killing potential will decrease. I see it as a buff to safety in lane when farming, but a nerf to her full combo. While a mage, she needs a full combo to burst a enemy. Her picking potential will decrease with this change.
Surely she is meant to be a mage, but she should be also be able to pick an enemy with charm. If you really don't want the dmg amp, then increase the CC duration at early levels at least, since peple don't max it 1st.
Most mages rely on their full combos to pick up a kill. Lux does it. Syndra does it. Liss does it. etc etc. And while this is a buff to her poke and safety in lane to farm, her picking potential will decrease due to the nerf on her full combo. Charm is an utility spell, not a damage one, and it should give utility.
TL;DR: Ahri's charm needs something more to reward the player or the full combo will be hurt. Keep the damage amplification or increase the CC duration at early levels.