tobehanabi; The Mega Rayquaza battle pack doesn't say anything about another Rayquaza/Mega Rayquaza. It only mentions Blaziken EX and two packs of Emerald Break, Gaia Volcano and Tidal Storm.
Barboach the powerful, I am actually curious to see/get the megas of the hoenn evolutions too, especially M. Sceptile. So far except for Reshiram, Zekrom and Arceus (who technically should have a fairy version too) everything that can be treated as dragon has been treated as dragon. So with cards like M. Sceptile (or M. Ampharos for that matter) what type will we get?
I really do want Zygarde to come out, but I don't see it happening until the end of the year or beginning of next, when we learn about Pokemon Z or X2/Y2, whatever.
Actually, at least in my opinion, four megas is a good way to go. That would take about 2 years (bar any new ones in the sequel games) give or take a few that could be released in premium collections in the vein of Mega Metagross and Mega Diancie, which is also how I see getting Mega Absol honestly. This could work for M. Sharpedo EX and M. Camerupt EX too, since we already got their EX versions in Primal Clash but no sign of their megas, which is odd given their current pattern as I mentioned earlier. And if the gen six card era lasts two years, then there we go. All megas before gen seven. Not to say it will happen but I think this would work well.
I think we'll get the Blaziken EX in this set, but it will be done in the same way as Hawlucha EX, where we only have one, no full art. That is really the only way to account for an odd number of EX Pokemon in the set:
Rayquaza EX
M. Rayquaza EX
Latios EX
M. Latios EX
Unknown EX one
Unknown M. EX one
Unknown EX two
Unknown M. EX two
Thundurus EX
Hydrgeion EX
Blaziken EX
The thing is we haven't always gotten legendaries (duo or otherwise) at the same time though it is highly rare not too. For example Tornadus EX was in Dark Explorers (and reprinted in Legendary Treasures as a promo) but until now never got a Thundurus EX. I don't count the Therian formes here. And of course we have the infamous missing Suicune EX when they did Raikou EX and Entei EX, whereas in contrast we got Articuno EX, Zapdos EX, and Moltres EX together.