Although this isn't Pokemon, a Sailor Moon anime series is going to be released in July in Japan and America.
You, intentionally or unintentionally forget something: that almost every DA episode is revealed in that poster and they don't have enough episodes to cover until October. Remember that when Iris and Cilan leaves (leaves and returns) the series is over.
It's very rare that the BW anime will last until the end of September/early October and aired the new series like AG and DP.
Exist three posibilities to do between the end of Best Wishes and the release of the XY games in Japan. (I consider a early release if it the series started in September or second half of August).
-1) Air the XY series early.
-2) Air Iris and Cilan special episodes and air XY afterwards early (With a transition epsiode between the specials and XY).
-3) Airing a series of specials until XY's release with air very close (<30 days) with the dub.
-4) Airing reruns of past episodes and air XY with the games' release.
Remember that I don't beleive anymore that the anime is ending in Japan as usual because:
-The BW series seems as finished, specially after Episode N.
-Very few promotions about the DA sub-saga compared to Episode N and Season 2.
-The movie being placed in April.
-Revealing the possible departures of Iris and Cilan very early. And with it, almost all the DA saga. And remember that this poster isn't a leak of something that shouldn't be revealed until months after.
-Ash not having any role to do in DA. If DA was supposed to last longer (25 episodes) it will have a mini-league like OI.
In my personal opinion, I think that they will air a mini-series of specials. Because I think that it will be a Iris episode witht he village of dragons about being Gym Leader, a Cilan epsiode about the gym and their connoseiur career, Brock and Dawn episodes based on the sets of Banpresto. And if I'm further I see a episode regarding Bianca/Juniper and an episode regarding Team Rocket (I said a TR special episode, not a TR finale). And an Ash finale episode where Ash goes to the DA region. That could make 7 episodes, the same as the gap between the end of BW and XY. The Xy series would start as usual in October and they start the dub in November (based on Takara Tomy's announcemtn (yes, Tomy control todays internationally now) that they will release in America toys in November.
Although I will have many cautions (the August 2012 BW kids set don't represent the anime) I will look forward of when it's revealed the list of Bandai Bw kids set for August. This could clarify many things about what is happening based on the contens of the set.