What gets me is that in the last scene in Crystal Skull, Indy is just a participant, not a driver of anything. He and his gang go see the aliens, Cate Blanchett wakes the aliens, and everyone just watches them blast off. That's it. You could claim that's the case in Raider's as well - they get tied to a pole and that's it. But at least in that movie, there was mystery behind the ark. Nobody knows what's going to happen when the Nazis open it. That anticipation is what drives the ending. In Skull, there is no mystery to any of it, and therefore little to anticipate. From the first scene, we know there are aliens involved (don't we even see a body at the beginning?), so when they finally appear, it's no big deal . In the end, the movie relies solely on "cool" CGI to create the wow factor.