I love the first 3 Die Hard films, so I'll always watch four with an open mind. After all, it did take me a while to warm up to Lethal Weapon 4, but I do enjoy that movie now, even though it is the weakest of the four films.
As for some news on five, rumor has it that the runtime is around 90 minutes. This is a little troubling, as the last four films have all been about two hours. Makes you wonder if it was either a longer movie, or an R rated movie. Like Fox wouldn't let them have both. Now I know a shorter running time doesn't necessarily mean it will be bad, just that it might not be as big on story or character as the first three were.