I really hope Dawn stays. She has so much unexplored potential. For one thing she just got that Togekiss a few episodes before the GF, Cyndaquil is just a baby, and buneary is yet to evolve (I really hope it does.) I personally hope that they have the boy b/w character on the team for a change.
Why would they do all that? Dawn's had Buneary for 180 episodes, if it was going to evolve it would have happened. And why bring up Cynda or Togekiss? They're done development wise.
Dawn is 100% leaving. There's no way her or this Contest dynamic will last past 4 years. This set of coordinators weren't even that popular.