I would have respond earlier, but my post got accidentally deleted.
-Do more with her pokemon and learn how to bond with them on closer level like its case with Iris.
-Have her involved with villain arc which was heavily linked with water/fire type making sense for dedicated water trainer to play role in there.
-have her gain knowledge from other one type specialists as mentioned before
-contests are possibility too, but on occasional basis serving more as stepping stone to develop flexible, defensive style helping her in future career.
Also if by any chance May still joined cast this could had soil ground for new type of chemistry in cast making me believe that AG would be imbued with more energy and life within such set up, offering many interpretations to build on relation between companions and make things more exciting.
If character wasn't explored enough having potential to be done more through continuation im personally always in favor of instead of discarding have invest more into him enriching his past, story and personality.
Dunno i always thought AG would have been more fun to follow if this had happened.
I have hard time believing how "people"didn't cared when i see exact opposite with bad reputation of certain saga=/=affecting their appreciation for characters.
Likewise writers already wrote better for Misty in Master Quest giving her development and focus on her goals, being carried through specials after leaving. So im of view how her handling would be even better following writer overall improvement in way show, pokemon teams and characters were treated in AG which was step up in certain areas over way this things used to be handled before.
This issues were there from start only deepening problem over time and limiting Shudo liberty, thus increasing frustration about way in which show should be constructed.
Also for record he was in charge of doing series construction for first half of Johto region deciding what should happen there. Which was in my opinion inferior compared to later half, especially during Master Quest which had may arcs, good development for Ash and sidekicks being better plot based.
Speaking of character replacing when i look at other shows which instead of discarding, invest more into characters building on what they established before about stories knowing how to do continuation without losing steam i keep wandering why not have Pokemon do the same?
Maybe its just me, but i would rather have pokemon be more like One Piece, Naruto, Winx etc. Not to have same mature content, but more in sense of having constant, continuity based storyline with characters we grew up growing in new, fresh directions gradually developing instead of getting constantly new ones being deprived of chances to ever get stable cast.
Whether its popular or unpopular personally i don't support cast replacing not seeing any point on constantly adding new companions if all development and story writers started about them, experience they gained, pokemon etc is going to end up unfinished leaving cast and going way of previous characters ending forgotten and buried in past. It makes it useless for me to grow attached to characters anymore when its known from start how they will end up, damages continuity and series reputation, giving us in end shallow story and practically erased continuity at start of every new generation.
I surely don't see any point in this making me ask myself when its time to draw line and say stop? How many more new characters we need to receive, when there exist potential to do many interesting things with previous ones already having background and predisposition to receive sequel, advance their dreams in more profine way already having experience and developed relationship with Ash and others allowing for its build up?
Personally i know i would be more interesting to follow story of already somewhat developed character going on bigger things regardless of its Misty, May, Brock, Dawn or Iris, and see in what new exciting directions writers can take them. As opposite to overused predictable formula of constantly replacing characters like they are on assembly line replacing them in half of development eventually fading away never to be seen again.
Nevertheless how to expect seeing this show move forward instead of having messed up plot, inconsistent development and "status quo", when every time opportunity to do build up on already existing friendship Ash established with current companions and already developed story which could be carried over to next region taking things forward gets flushed down the toilet once characters gets replaced taking away loyalty and eagerness in staying tune toward this anime?
But hey that's just me finding there exist alternative to this formula and issue of constant cycling which in longer run brings nothing positive.