Personally i still like Ash and his naivety, brash attitude and competitive spirit striving to become best. Mixed with childish and well intentioned demeanor putting lot of effort and care in pokemon often putting them in front of himself.
Though i can understand people who are tired of repetitive, endless cycle hes been stuck into because im on same page about this too. But question does arise, is it worth the risk to try to replace serise mascot and lose people loyalty when writers could just instead fix mistakes and change current approach taking him on higher level?
There are plenty of things going for Ash which could breathe new life in his character and make his adventures engaging to watch, being shame to have prospect for all exciting directions he could be taken forward go to waste.
He still didn't won league, didn't challenged E4, champion etc not being even close to achievement of pokemon master dream. There are many things left unexplored about his past, such as father who could be introduced at some point being portrayed as master himself serving as ultimate test for Ash to prove if he has what it takes to become "best". Aka father vs son showdown.
Writers could expand on whole connection to Ho-oh being said how this pokemon shows himself only to special trainers out there giving some background, explanation about this.
We could see him after winning league leveling up as trainer learning how to develop new battling style, enter special harder challenges like Battle Frontier was, entering other leagues he didn't won and battle stronger trainers. Heck there could be whole tyoe of league foir "Masters" someone earns right to enter after winning champion league having completely new, unseen concept of tests and evaluators you need to pass to prove yourself worthy of title of pokemon master.
In DP Lucian himself said how winning champion league is one of steps someone needs to conquer on road of becoming master, but its not only one. So we don't know what other challenges and complex tasks(like Battle Frontier was for example) Ash would need to accomplish before he becomes recognized as strongest trainer in world. Character wise Ash also has many flaws which stand on his way of becoming successful and respected trainer one day too suffering from immaturity,being naive and prone to doing foolish mistakes at times acting before thinking etc.
So he definitely has potential to go through more significant development bringing whole new enjoyable outlook on it.
When i see Tyson or Gingka from Beyblade who became world champions with their stories instead of ending receiving sequel going through deeper growth. Goku from DBZ who continued to evolve and learn new things after defeating major villains or winning tournament, Dan from Bakugan who after becoming word renowned brawler went through harder challenges having new problems and tasks to overcome i know for fact how there could be surely done a lot with Ash after winning league as well. As already explained before.
Its only up to writers if they have motivation and courage to do step forward, and judging by decrease pf people interest, constant rating decline and negative critics they are reaching turning point where they would either have to custom things out and change status quo or sink down even lower.
Way i see it with Ash we could see already experienced trainer who has background behind himself going on bigger tasks reaching higher levels as trainer which means stable and stronger pokemon, deeper development, better battles, opportunity to dive more into someone history etc.
Additionally with him there exists requirements to take established character to new, unexpected directions having more complex growth.
Something you cannot do with rookies who are just starting out having to go through basics all over again.
Not if the studio hires new writers. Seriously, I think it's time for the anime to receive a complete overhaul, not just Ash. Although like I said, there is at least one way of making his character seem a little more relatable imo.
Honestly there still wouldn't be need for new protagonist since skills from new set of writers would just reflect on Ash development as character making better job with him and story.
If anime comes to an end, i would rather have it that they finish it with character with who started everything (Ash)treating this series as one big continuity, not making any new alternate series after this. Pokemon had pretty good run so far, and everything must come to an end eventually.
Better idea imo would be if pokemon tried out cast rotation.That way we would still get new characters, while at same time people being able to see their favorites from past(like Dawn, Misty, Brock, May etc) again in action and updated.
Such thing could create groundwork on which it is possible to leave long lasting impact on audience, increase their loyalty toward show and set up path for stable ratings and increase of popularity in future. Because anime which keep older characters relevant doing mix of both older and new as result while choose to invest more in current protagonist taking him on bigger and better things can become appealing not only to new kids, but older ones as well gathering large group of followers. Like One Piece, Naruto , Bakugan and similar ones are doing for years.
Rather than getting rehash of current series with new protagonist which will do same all gym quest, have Pikachu as main mascot and be rather similar to Ash character getting rid of all characters and everything which pokemon represented losing brand and charisma it build around itself.
Judging by massive demand for original trio reunion it seems to me how most fans just want better written show which pays attention to history and previous companions investing more in kmain protagonist and his companions they grew to like. As opposite to starting things without finishing them, which is in writers habit it seems leaving most characters unfinished.