What better way to distract people from your bad financial results than to announce a new(ish) Pokemon game!
Not much to go on from this teaser trailer, but they do keep calling it a new adventure so maybe it's a bit more than a simple remake of Ruby/Sapphire.
Pokemon Z would have been easier to make though. They had to recreate Hoenn in the X&Y game engine, Z could have used the same environments from Kallos, with a few tweaks and extra areas.