Or they think that every1 is still collecting medals in BW2..ala perhaps its slightly to soon to throw "new gen" news in our face, so they started with the shiny part (Ive seen tons of "next gen news"-fear amongst fans although I dont understand it.)
Aynway, last year, this time, we merely had confirmation that Kyurem will star, and a very vague hint at new forme for it. There was also an artistic detail to the movie title that looked similar to Keldeos red mane, but had we not hacked the games for it, we wouldn't have a clue it meant anything.
Only in the January corocoro it then hinted at a new pokemon reveal in February.
Also note that this shiny Genesect is gonna be distributed before the movie.
Makes me wonder what the main event pokemon will be. A random guess is, something Eevee related that will unlock something in whatever upcoming game (what is it with the continued eevee hype??).
Like how Celebi and the beasts turned out to actually be the only way to even get a Zorua in BW. I very much disliked that, but I can see them do that again with whatever the main role turns out to be.
What other movie had shiny versions of already known legendaries as co-stars? The Zoroark one.