She was complete trash before the charm buff LOL. Pro players discussed she was trash and many ahri mains considered her trash. Even riot considered her too weak. She needed a buff regardless but she got a buff that doesnt solve her problems.
The only reasonable nerf to ahri is to revert the charm buff and instead buff her damage. Buffing damage would mean her winrate will be less since utility buff is more powerful than damage buff(though too much damage is also strong though).
If ahri can burst with e w q, what is wrong with that? She landed a difficult skillshot and landing all her skillshots. She used around 75% of her ability and even perhaps electrocrute proc. Which alone should mean she bursts the enemy.
You say Ahri should only burst squishies, which is fine if she can easily do so. Like how u said ahri is obnoxious if she can burst with e w q, but if Riot makes her R do damage, then ofc it should be included in her damage. But, look at Akali. She could kill people with or without her R. Her R has a very powerful stun and an execute. That spell alone with perhaps an auto will most likely kill a squishy.
Champs who has more risk to apply dash has easier time applying that damage once they get in range. Look at Akali, Zed, Talon, and Leblanc. Ahri does not have mobility pre 6 like them, so she doesnt have a constant mobility to label her as Assassin. She doesnt snowball as hard as them since she relies on landing skillshots. If she can't land it, no matter how fed she is(unless she is crazy fed and the enemy is crazy feeding and is Squishy).
If Ahri has to use one ultimate charge to commit while having the importance to land skillshot which is already difficult to use, what is the point of it? Other champs can kill people without ultimate like Syndra and Zed once they are fed.
So why does Ahri have to use ultimate to kill? Her ultimate cd isnt as low as Leblanc and her ability set is not as forgiving as Leblanc who can just blink back if she messes up. If Ahri does miss charm, against any player who actually uses their brain, Ahri is good as dead or will have to ultimate away. With so much risk of landing charm, then having required to use 1 ultimate charge to kill a squishy, well you are also ignoring that a fed ADC can just right click to chunk people from like 800 range. How is that fair?
So Ahri has to use ultimate to basically "comit" to burst when other champ doesnt need to? You are completely ignoring Ahri and her kit. Her kit is really weak as is and you make Ahri even weaker.
Her time was only strong during dfg time because her W and R had respectable range and damage. Now it is only used for bursting.