It's funny how here in France, some comments state "see how it's
Dragon Ball Z and not
Kai. That shows how
Kai was a huge unprecedented flop in the history of anime".
Hum... I don't think so.

It would just be dumb to call it
Kai when "Kai" stands for the notion of old material being remade or refreshed, while the movie will likely focus on new material. That's all.
Anyway, it's too bad that there's no additional information with the end of the countdown, but not too surprising: we're like 8 months away from the release, so they have to keep enough information to keep us entertained for all these upcoming months while still not spoiling us too much. So we shouldn't expect too many information too soon, especially about the plot...
It is even possible that they have made the announcement before even having ideas for the plot, and they might actually check the fans' reactions to see what kind of plot they might like for a potential "best movie ever" and start developping the plot. Well, at least it seems they've decided what era is involved (since we see Goten and Trunks). But even that might be unsure, since we see characters with outfits for several different eras, so maybe we just have a generic artwork for now to cover all eras until they decide the plot.
But likely, it will be like the 2008 movie: focusing on the era after Majin Boo was defeated.