I like Mega-Swamp because it looks visibly different. May sound strange, but Mega-Sceptile looks too... boring. Too much like the normal one. It should have something... more. Maybe I need to see the artwork first in its full glory, not only a scan. But I had hoped for something better, like a samurai mantle and helmet made out of plants and sword sheaths on his back/sides, also made out of plants.
But I'm really happy with prehistoric Groudon & Kyogre, I'm curious on how that devolution thing will turn out. Like a mega evolution, but with a special animation? Or like a form change, its permanent until you dont want it anymore?
My theory before the remake was announced was that if they make a Hoenn remake, the red & blue (and green) stone would turn out to be mega stones and unlock Groudons, Kyogres and Rayquazas true potential. Maybe I'm still right. Also, they totally should connect Hoenn and Kalos by saying that the stones that were used to calm Groudon & Kyogre were made in Kalos and were a gift of the former king who wanted to help the people of Hoenn.
And I want an extended backstory on the golems, I always thought their story was really cool and the way to unlock them was pretty unique. Hell, back then a friend told me about them, I didnt even knew they existed in the game. And using the manuel with the braille-code to unlock their chambers was really fun.