Well, Let me think for a bit.. I remember how it ended with this space ark activating and the presidents coming out (Lol I didn't even recognize who they were the first time seeing them). Seeing as the Ark was activated by the ase and the presidents coming out, I'm just gonna assume that the Ark is where the presidents were in or whatever. Since adam is dead, I think their is def. gonna be a greater evil since the chick says "You who doomed us all." I'm sure this has been said before but I think time travel will play a role in the next game.
The new evil... hmm.. what if it was someone who was evil in history? Like hitler or Genghis Khan who were actually progenitors in disguise. Idk, just a though.
Because I'm only a crack in this castle of glass. If you get the reference then this is for you... <3