Agent Spalko said:"I go first Indy..."
That line always cracks me up but it's so over-the-top camp that I can't take the first half of the film seriously at all. If the film had taken itself more seriously like Raiders it would have been a masterpiece.
I don't think there's any way Spielberg could have played Doom as straight as he did Raiders. Everything in the second movie, from the cartoonish mine car chase to the spooky villain to the crazy, over the top temple itself, was just too silly and comic booky in nature to ever be taken THAT seriously. He pretty much had to camp it up to make the story work.
And frankly I don't think a more toned-down, realistic temple and villain would have been nearly as much fun anyway.