This is what I want-
--Ash get hurt Protecting Serena .
--Serena feel guilty for being weak and getting Ash hurt to save her.
--She temporarily leave the group and train in ''Battle Cheatu'' Or ''Battle Maison'' to become stronger .
--Korrina Or Shauna take her place as main girl .
--After a bunch of episode later , Ash is outnumbered by Villainous team grunt and he need help.
--Suddenly Serena appear to save him .
-- Now She is strong and has completely different personality then before .
--She become more like ''Y'' (Pokespe) ! Strong willed , Determined , confident and more Sassier .
--She love Ash but doesn't treat him like a idol anymore ! Therefore she has more intimate relationship with Ash where she can easily show her Sassy side toward Ash.