I think they could possibly build on the fact that Tsutarja was getting neglected in terms of battling and feeling underappreciated. I've never seen why a Pokémon hasn't left Satoshi on bad terms yet for a sense of realism; people do not always match and so I don't think that Satoshi should always be able to work it out with his Pokémon in the end.
I was thinking the same thing. It could be a great storyline if written correctly.