The sense of entitlement here is crazy. The original trailers didn't suggest at all that Misty, Brock, Gary or any other old character would be appearing. It only showed that beginning would be the very first episode, with Ash starting out on his journey, and that this time around it'd be different. Fans then speculated, on their own, that all the old characters would show up. At that time, it was a genuine possibility. But it was only that: a possibility. Without suitable information people hyped themselves up to the point where anything less wouldn't be good enough. This is the result. People acting like their expectations have been betrayed when the film never asked you have to those expectations in the first place.
I mean, come on, spitting on Pokemon's history? Disrespecting the fans? Are you guys serious? This film that starts at the very first episode and explores a plot thread that they've left alone this whole time is somehow spitting on Pokemon's history? This film that isn't catering to your desires is somehow insulting?
Frankly, it's all so stupid to me. Disappointment is one thing. People can be disappointed that certain characters aren't appearing. I get that. But ffs some people need to get a grip. You were not promised anything. Nobody came out and promised a remake or a retelling of the original story. Nobody said certain characters would appear. I'm not saying you have to like it but this constant overreaction to what this show does - the Kalos League, SM's announcement, now this - is just tiresome.
Back to the new characters thing, the argument that people will forget them therefore they're pointless isn't making a whole lot of sense. With every new film comes a new part of the world and a new story. Naturally, new characters SHOULD follow, because they're vessels for this story and world.
I support this decision, not just because it makes sense to me to tell an original story with original characters designed specifically for the story, but also because it's something different. Nostalgia isn't a bad thing and there's plenty of nostalgia in this film already. But I do feel that the moment a franchise starts relying on nostalgia to drive things is the moment they admit they can't come up with anything new or interesting.