Why Ahri is fine where she is...
Ok first off, Ahri is one of the most balanced champions in league of legends. She has been that way since her creation, which is why for the most part, riot has left her alone. The biggest exception to this rule was when charm acted as a mini DFG, riot got that off the fox real quick. She is not incredibly strong nor is she incredibly weak either, she is right in the middle. 2 of her skills are skill shots which means they have a chance of hitting, people who play her either have to appropriately lead their shots or land easy hits on afk people.
Which brings me to my next point: we are basing this on low level play. While I am Bronze 1 and can't say "I'm a pro i know what I'm talking about with champion balance," I can say I have played enough bronze/silver games to tell you that playing skill shot champions is not hard to play at all. I have mained Ahri since season 2.5 and if i have learned anything is that opponents are easy to predict. People tend to be stuck in a rut of play at lower levels that's easy to pick up, almost like a habit. If you throw out 3-4 skill shots and hit (or mostly miss) because your opponent is trying to dodge them, you can easily see that they start to lean towards a certain movement pattern, that even when they are continuously hit afterward, they have a hard time correcting it. Most Ahri's will also try and set up their Q to hit at the end of the path as well because that is a reliable source to get both sources of damage on at once. So really, it's more of player faults then champion faults.
Next I will talk about skills, her Q has 2 sources of damage with the second hit being much harder than the first. As i said most Ahri's will try to set their Q to hit at the end of the path rather than try to shoot past and aim it back. Her W does prioritize champions but each flame has it's own range that it will travel, meaning that when she activates it, it doesn't just choose a target over a certain area. So even though one flame is nearest you and your in it's area, doesn't mean the other 2 will hit you as well, especially if minions are nearby and they are in the hit box and not you. Her E is a slow-medium moving skill shot that can be easily dodged, and whose hitbox is actually smaller than the animation. Charms can easily be dodged, and even so, early to mid game she requires at least 2 if not more rotations to finish someone off 100-0, so if you get caught out twice or more by Ahri that's your fault, other times it's just poking with her Q until your low enough to be engaged upon. Finally her Ult can be on the annoying side, either when she is engaging or disengaging, but even so, she doesn't dash so far as to be completely removed from danger as most Ahri's will save her dashes defensively when she is low on HP, which a flash-spell will usually finish her off.
Ahri is not strong, but she is not weak. She has her counterplay, but she has defensives. Shall we say nerf Vlad because he can heal with his spells and become immune to all forms of damage for 3 seconds? Should we say nerf Gnar because mega gnar gives him more cc and tankiness? No, but ahri is in a good spot at the moment, nerfing her will just create more problems than fixing them right now.