
that image pretty much says my idea, plus adding to this new world the planned Frozen dungeon, and the new things from aether II (the new clouds, ores, trees, etc)
in addition of that, new type of sun spirit dungeon; inside of a nether fortress (since this new aether has nether islands, then also should have nether fortresses) or perhaps a new type of nether fortress made out of hellfire.
and if is possible, make the new type of bronze dungeon, (but with some tweaks of course) or maybe nether mounts

i think that this could add a whole new level of adventure, because the zephyrs will be joined by ghasts, dangerous landscapes, and if possible, PvP (but with regions that makes the place non-pvp)