How TF is she a better written Misty? Iris has an annoying and unlikable personality, she doesn't work at all to earn the accomplishments she has gained over the series and all of the accomplishments she has achieved, aside from Axew mastering Dragon Rage, were practically handed to her. Plus, they didn't go out of their way to make Misty look like a gifted trainer when she was just about average like they've done with Iris.
From the very beginning Iris critsized Ash's abilities, not even knowing his skills or history as a trainer. And then she turns out to be no better by having a weak Axew that gets hurt by a weakened Bullet Seed and a disobedient Excadrill. Not only that, but all of Iris wins were handed to her through cheap battles and overpowered Pokemon. Overall, Misty is the one who is written better than Iris and is actually able to get valid wins without disobedient OP Pokemon so don't come up in here trying to say shes a better written Misty. Actually learn how to watch a show for Gods sake.
Really they're both hit and miss, but nearly every complaint you dealt Iris can also be given to Misty, just of a different variant.
Misty ALSO critcized Ash despite being just as incompetent as him at the start of the series, even with more experience. BOTH of them were designed to be hypocrites, just replace Iris' pomposity with Misty's aggression.
Misty also seldom won out of her competence until about the very end of Johto, you can not talk about disobidient OP Pokemon without taking about Psyduck, who interrupted just about EVERY BATTLE SHE HAD. She failed to train or work with any of her Pokemon's defects to be effecient through her command and relied on them disobeying her in a convinient way for most of the OS, just like Iris' Dragonite, only Iris at least got called out on it and tried to resolve the problem, while Misty tried once with Psyduck and Togepi and then gave up and sulked until SM's offscreen development, while Starmie and Horsie just got forgotten about completely.
Similar to Iris, Misty got plot armour and skipped over several important beats of character development. Johto barely focused on her and then randomly decided to make her competent in the last season. This felt little like something she worked for, especially due to the aforementioned ragequitting on most of her team.
The moment Axew learned Outrage out of nowhere started the Mary Sue-ish treatment for Iris. There is just no excuse for Axew learning moves like that and Giga Impact with no training or difficulty when it took so long for it to master a basic move like Dragon Rage. Dragonite certainly didn't help with that treatment though.
While Togepi knowing Metronome and Psyduck knowing Psychic is more grounded in terms of their skillset, they were still never learned or commanded through Misty's training, they always worked conviniently perfect, and never did any opponent manage to counter or deflect them, making them seem like an equal unstoppable plot device for her as Axew and Dragonite for Iris (who at least LOST sometimes). Misty fell upwards just as often as Iris did.