we came to the conclusion that while Die Hard had done so much in fresh and interesting ways at the time, it had been so thoroughly copied from by so many other films that it offered little to an uninitiated modern audience, looking back.

This becomes SO obvious when you look at "the great classics". Citizen Kane is, by all modern standards, a pretty boring and uninspiring movie about a really lame topic.

But at the time, it was absolutely groundbreaking. It basically pioneered half a dozen techniques such as "letting foreground and background be in focus at the same time" and "nonlinear storytelling" (which of course was hugely telegraphed, because it was new) and "using a montage" with "Sound to make transitions". He also used such amazing techniques such as "long takes" up to several minutes. He moved the camera around, not just taking a stage-view, but low and high angle shots, and then he added lighting to make things stand out.

Stuff like that is now SO basic that they might not even teach it in filmschool, simply because people are inundated with it from modern media. Orson Welles basically invented all of that though, and it was revolutionary. Now it's just boring a movie about an asshole's sled.