I honestly don't care too much for Greninja, so I wouldn't really care if it came back. Although if Greninja did return, then most likely the other Kalos starters would have to as well. I would've liked to see all of the starters other than the Hoenn ones return in the Crown Tundra, but I guess not. Other than that, I'm actually pretty satisfied with the roster in general. I assume that the roster now is final, so I will now pay respect to the Pokemon I really wanted to see, hopefully, they'll get in next time.
RIP: Cyndaquil line, Totodile line, Sentret line, Mareep line, Deoxys, Turtwig line, Piplup line, Starly line, Buizel Line, Darkrai, Shaymin, Snivy line, Oshawott line.