Maybe Monoferno's problem will be that it will be too hard/hot to handle.
I think they did everything they could do:
Charmeleon not obeing...
Sceptile can't attack...
Turtwig biting his head...
Buizel being stubbern...
Aipom (before switch) taking Ash's hat...
What else?
A lazy Monferno maybe?
Infernape learning to control blaze without killing everyone and everything around it?
Monferno doesn't need to be anyone's clone. It can have his own character, his own battling style and his own quirks and personality.
Maybe it could be kinda dumb when it evolves? That could be it's "thing".