When I first saw this trailer, I initially thought "Wait, is this a new anime series?" Then I came to the realization that it was for the games, and thought "The anime really needs to be like this!" Anyway, on topic, there's one thing that I found very intriguing about this trailer. The player is chasing the Shadow Triad through a city that *is* truly frozen. Now, I was thinking that the ice on the map was just covering up changes they made, but maybe I was wrong. I still can't know for sure until the games come out, though, because for all we know, that could have been a different area entirely.
As far as the rest of the trailer, I like the fact that Team Plasma is apparently still going to be the villains. The way they're dressed looks like that team we saw in the gameplay trailers that the rival was talking to in Nimbasa City. Also, despite Cheren being a gym leader now, it appears as though he might be a recurring character throughout the game, helping you fight Team Plasma. Elesa is still a gym leader with a new look, so that makes me wonder who else is still a gym leader, and are there any other replaced gym leaders?