Yeah, they are having issues coming up with the story for the third movie, especially after the second movie didn't do so well in terms of ticket sales.
I am still wondering that myself :P. I got Sapphire and Emerald back in Gen III so now would be the time to play the Magma story. Also Omega Ruby is likely to have Latios exclusively (until an event) and I want one as I have a lot of Latias' to transfer over already, but only one Latios. But I sort of want Alpha Sapphire for the nostalgia...now if only it were Delta Emerald that was being released I would get it in a heart beat seeing how it will give me both nostalgia plus we got to pick our Lati (and a better story over all).