That is what they should have done, have her end up becoming the new gym leader. Drayden felt completely wasted, neither her nor Ash got a battle in with him.
Iris really should have faced off against Drayden for title of gym leader. While Ash fought Marlon for his eighth badge. No need to have brought Roxie or Charon in, Gym Leader Charon anyways.....
Type master is just too bland a goal, Misty should have been the only one. May and Dawn were a good step forward for handling female characters, but after that they seem to take one step backwards(BW), forwards(XY), then backwards again(SM)
Like it'd have been perfect to have Bianca and Cheren as Ash's rivals, and Iris striving to be the new Opelucid Gym Leader.
And in the end, Iris ends up beating Drayden for his title as gym leader, Bianca loses to Ash in an early round and rethinks about her life before signing on as Juniper's assistant, and Cheren ends up becoming Lenora's apprentice wanting to work towards being a gym leader after Ash finally beats him and he realizes that he'd like to help other trainers overcome struggles and work towards their future.