I'm fairly sure there's one point in the video where the male protagonist is running in a forest, and there's a girl following behind him. (I'm pretty sure). That's what I thought this thread was going to be about (maybe she was the rival?)
I really don't know. I think all the rivals have been fairly different right up to now:
We had Blue, who was immature and bratty but a good trainer.
We had Silver/whatever, who was nearly evil but eventually saw what he was becoming.
We had Wally, who is only battled twice in the story but still grows a lot. We also had Brendan and May but they barely count, to be fair.
We then had Pearl/Barry/whatever. He was hyperactive and simply grew- a lot- as a Trainer.
I think N counted as your true Rival in BW, and Cheren/Bianca were.. different Rivals. :P But they all had REALLY interesting stories, which was refreshing and simply great.
Just like Hugh in B2W2, who wanted to be a great trainer and also had.. well, anger issues with Team Plasma.
I just hope they manage to make the new rival(s) as interesting as all of them so far!