There is a formula to these movies but I love the formula. It always John McClane- stuck in a terrible deadly situation trying to do the best he can -and always being put down by the "authority" figures- the professionals who SHOULD be able to handle the situation, trying to push him out of the way-stop him- or ignore him. Then he- with the help of some ordinary (non-professional -not a soldier or FBI guy or SWAT team member) giving him help- the Twinkie cop in 1 and 2; the chauffeur in #1; the guy in the basement of #2; the Jackson character in 3 and the computer geeks in #4. He- and the non-pros- end up saving the day - often with the smart ass "superiors" ending up dead or looking REALLY stupid- i always think of the FBI guys in the 1st movie who are so arrogant and dismissive of ALL the local people ending up blown away.
i think I've always liked situations where the best win- not just the people with the credentials - to paraphrase SPOCK when explaining to Dr. McCoy why Spock should go on the dangerous mission, not the doctor. The same theme was in TWISTER an I liked it there too. I'm hoping there will be a #5.