Misty had less screen time in Johto compared to early Kanto. She was in the background most of the time. She did get some development like the whirl cup, but still wasn't enough at all. We need more than that. Her story was unfinished, sad.
In a way Misty character development in Kanto, Orange and later half of Johto followed different direction being mostly focused on Misty personality, emotional growth rather than focusing on her career of becoming water master and variuous ambitions she may had(like Dawn for example had which grew as coordinator but barely changed as person). Her development was more gradual happening due to line of various events, issues she faced against and circumstances leaving effect on character. Along with sometime experiencing direct change through episodes like overcoming Gyarados fear, learning to understand better water pokemon like Marill when saving its life, growing to like Psyduck despite getting on her nerves or sharing her own tragic past and childhood with Ash and Brock revealing how underneath rough surface and tough attitude is hiding insecure girl, full of fears and desire to be noticed and acknowledged for her qualities.
As time went on through individual episodes where writers dived in Misty inner thoughts and personal feelings over someone or something, moments where she struggled, had selfdoubts about her own appearance, skills as trainer and various issues not being sure where she stands as person; changes began happening within her molding to become person she was and is today. Subtly but notably starting to mature and evolve.
Because of that i feel emotionally Misty changed more than any other male protagonist beside Ash and out of girls only May seemed to change to such extent as character like she did making it seem like all struggles and failures they went through, challenges they had to overcome , personal fears and development of new skills had them evolve as characters becoming stronger as result of that. While always staying true to herself with writers exploring more facets than just nagging and complaining which made Misty feel complete and multidimensional.
For instance in Orange Islands she showed more of her romantic side liking to flirt and pair other couples together like Nidoran couple, in Johto we sawed more of her spirit and passion for battling and water types, spirit for adventure falling for romantic and cute stuff(Teddiursa thief being one of great examples). along with snarky side becoming more centered on teasing and moral support .
Not everything was handled good, consistent and adequatelly paced , but at end of the day Misty became more mature, filled with independence and selfesteem discovering her own talent and qualities she posess as person proving strength to several people out there who underestimated her trainer skills and knowledge., As well more open and compassionate toward her friends and others being able to connect with people who suffered from same issues as she did using her own experience as medium to help them overcome theirs without losing her appeal remaining that same adventurous girl with lot of spunk who liked to playfully tease, stand up for weak having that fiery passion for competition.
But yes it goes without saying how Misty left prematurely leaving much more to be desired and be explored about character.
She is great character being mistake to have her leave considering how writers left lot of untapped potential for further development unused, lot of things about her past, goals and ambitions unexplored resulting in getting dumped with no resolution to story met, using gym as last minute excuse of keeping her out of cast. With specials after departure while offering some great growth not providing any real resolution to various plots of story centered around her with whole future and in what way dreams and desires will play out being left uncleared, open..
Like goal of water master and further expand on what it entails, potential to do more with her pokemon team, explore world and learn about water types and various cultures as much as she can. To fact of writers never fleshing out Misty and her backstory enough leaving lot of things to be desired and veiled with mystery about unresolved flaws, issues, lack of resolution in understanding pokemon feelings on close level using them to full potential etc.
True he was still enjoyable personality wise in AG, but it didn't feel like he was going through development anymore. I think that's the topic. I liked Brock in AG but felt his development ended in Johto.
Honestly I thought Brock's AG clothes made him look cooler though.
I guess it depoends on what each of us considers to be character development than though. I dont feel need to reinstate my points once again(did it at least three times in this thread)but personally i felt Brock continued to grow as breeder, showed signs of starting to consider shifting his career toward something else and came on better terms with his family). Being one of reasons why i felt staying in AG brought him more benefit than hindrance.