Apparently he's fed up with what has happened to the action movie genre. In an interview with Maxim magazine stated the following:
''They (the films) ran out of gas, and they ran out of bad guys. The genre started eating itself."
''You have to offer something more intriguing. It goes back to the films of Otto Preminger, or the thrillers Alfred Hitchcock made, where you never know what is going to happen next.''
He certainly has a point. I mean how much bigger can the explosions get or how much more convoluted can action sequences become? These days the audience needs a bigger and bigger action sequence "fix" in order to stay interested. Shaking things up a bit would be a good thing IMO.
Having said that, I am certainly a huge fan of the first three Die Hard films.
Source: New York Post Online