As soon as the groundhogs popped up I kind of figured I was going to be watching another Lucasfilm cartoon. That is the big problem with the movie for me, not the events themselves but how over-the-top they were able to make them now that the technology allows them to do anything and everything as big as they can dream it up. There is no bargaining with the realities of physically accomplishing something to compromise that dream image into something that looks plausible and, importantly, retains enough reality that it still feels dangerous. As far as I'm concerned it sits next to the PT on the shelf of movies I wish I could just pretend never got made. I don't doubt there was a good movie in there somewhere, but what ended up on screen just wasn't it.
It wasn't the content of Indy IV that spoiled the movie, it was the pacing and lack of an engaging story. The content was no more unrealistic than any of the earlier films. All the films had some kind of magic quality about them, and over the top stunts--even III.
He and his dad crossed the seal so the grail effect would no longer work - something like that. Might be remembering incorrectly.
The others didn't have 200 pounds of archeologist in them. They went much higher and farther than the camera could capture.
If we're looking for realism, then Indy would have probably died as a teenager running around on top of a moving circus train while bad guys were shooting at him.
Running on top of a moving train doesn't kill you. And "not getting hit by bullets" is not "surviving a nuke in a fridge".