Im not sure if i see problem in here.So Dawn has been showned cheering for Ash(it certainly wasnt first time),and all of a sudden people are making big deal about it like "thats all she will do now".
While its obvious how focus will be more on Ash and whole league altogether for understandable reasons,Dawn will still get some screentime and couple of episodes to herself.
She got plenty of screentime so far,so taking a small backseat while Ash competes in league isnt problem at all.Theres not much she can do during that time either.
Not to mention having her leave before league ends would be pointless.None of girls left that much primaturely,so why should Dawn be exception.She is guaranteed to stay around at least until Sinnoh league ends.
Unlike Misty, Dawn's cheer-leading spot is only temporary.
Misty pretty much sat back and yelled at Ash whenever she saw fit. She didn't have any sort of competition to train for
Contrary to your belief Mistys role was more important than "just sitting on sidelines"She along with Brock provided moral support,saving people lives,helping Ash to grow as trainer coaching him and pointing out mistakes.
Nevertheless she had plots centered around her like complex of inferiority,togepi,goal to become water pokemon master etc.
While Dawn obviously did more,Misty still had share of achievements like Princess festival,seaking contest,big involvment in arcs like st.Anne where thanks to he intelligence and quick thinking lives were saved,Whirl Cup etc.
Thing is writers didnt focused enough on her due to them not haing enough experience,aswell this anime being mostly oriented toward Ash.As time went on they improved in handling things better giving with each new saga to girls more focus.
or even bother training her own Pokemon.
Not true,there were references in older series where it was showed how she trains her pokemon off screen.Like when Marina complimented her pokemon saying how she trained them well.Ash mentioning couple of times how she did good job at training and so on.If needed ill list more examples.
I strongly disagree for I'm sick of every 3 years, we got to dump the girl character and put in another female character, and this one does not appease me at all:
You have no idea how many people are sick of girl replacing for stupid reasons just to give new "eye candy".Many people would like that this altogether stops giving older girls a chance to shine more,and to replace males for a change.
When it comes to me if contests arent being replaced i dont see any point in third girl in a row doing same thing.Better keep Dawn than and stop all this repetivity.
Of course my preference would be bringing Misty back who is great character and has so much untapped potential with her story being unfinished with goal being one of them which cant be achieved at gym.She would bring alot for this anime in my opinion if she ever returns.
But thats aside the pooint.
What im trying to say is how i pretty much agree with you,girl replacing should be stopped,instead of ditching them just to leave older ones who have lot of unused material behind in past being forgotten just to get new one which will receive same faith like other ones.
Question is how much more is needed?
I just cant picture Ash ending up travelling with about 10 girls once this show ends.That would be just disgusting.
Isn't there a risk in ratings if you keep changing your character? Is an audience in JP going to say you had something with Dawn, you gave her opp., then you took it and now you're saddling up with her with the JP character for Zoey?
Unfortunately writers dont care about fan wishes.I mean when Misty was replaced this caused big backlash with many people for years trying to bring her back through numerous petitions,letters etc,with demand for return to cast being huge,along with big group of them leaving this show in protest but nothing helped.
For years people are complaining about Brock wanting him replaced(poor guy),but he comesback every new region,etc.
As sad as it sounds writers only care about including another "eye candy" for male audience,interview with mr.Hidaka summed up nicely how they view girls in this show.