And here's a good commentary of the Ahri changes, and I agree with them:
"So here are the latest patch notes for PBE and unfortunately they bring sad news for Ahri players. First off they have increased the mana cost of Orb of Deception at every rank by 10 mana instead of 5, which makes it a big increase at later levels. Level 1 Orb has only been increased by 5 mana and level 2 Orb by 10 so the change won't make a too much of an impact early game but once you get to the later ranks in Q it will make a big impact on Ahri's mana pool. Max rank Q has gone from 75 to 100 mana which means that every Q you throw out will cost 25 more than before. To put this in perspective, right now 300 mana will get you 4 uses of orb of deception and with this nerf 300 mana will only get you 3 uses. Also, rank 5 orb will now cost just as much as Ahri's ultimate which is ridiculous. This nerf will make Ahri run out of mana a lot sooner mid-late game and you will be punished a lot more for missing a Q or using too many to farm/harass with.
The next 3 changes come to Fox-Fire and they also come as major nerfs. The first change is a straight up revert on the base damage buff it received in 5.2, taking it all the way back to the original numbers. This change is a seriously harsh nerf to Ahri because now it means that since losing the damage amp on Charm she has almost no compensation to her damage at all. They have heavily lowered her damage output pretty much just for the mobility on Q. I agree that the base damage on fox-fire should have been lowered but I did not expect a complete revert to pre 5.2.
The second change is the tiniest of buffs to fox-fire. At each rank the cooldown has been lowered by 1 second which honestly doesn't do a whole lot. The cooldown on fox-fire was never a problem and I don't really get why they decided to lower it by 1 second. It'll be quite nice to have more uptime on it but this doesn't even come close to making up for the loss in damage. The only benefit I see to this is that it will make kiting a little better because you will be able to cast W more frequently with a Rylai’s.
The last change is another pretty significant nerf and it's a 150 loss of range to fox-fire, going from 750 to 600. The reason that this is quite a significant nerf is because now you will have to get closer to the enemy champion for the fox-fire to hit. Getting closer means that you will be more in range of their abilities and easier to hit. It also means that you will be more likely to have the fox-fire charges wasted on minions if you are not close enough to the enemy champion. This change won't make a difference to how a full combo plays out but it will definitely make using it for harass in lane a lot harder and you won't be as safe when doing so.
I think we all expected Ahri to have some nerfs coming but these seem a bit excessive to me. If you pretend that patch 5.2 didn't happen and these are the changes that Ahri is getting after the removal of DFG, the only real buffs that she is getting is the movespeed on Q and slight damage/ratio buff to E. Yes the movespeed buff is quite over powered but I don't think it's worth losing a 20% damage amplification on charm, 150 loss of range on fox-fire and a large mana cost increase on orb of deception.
Ahri definitely needs some minor nerfs as she is extremely strong right now, but I really hope that Riot realise what they are doing to her with these changes and make the nerfs less gutting"