Well, apart from McClane yet again stumbling upon a major terrorist plot. And I don't think DIE HARD 4.0 has a clever, involving script, exactly. It's meat-and-potatoes, by-the-numbers stuff that just strings together overblown action sequences and tired wisecracks, mixing them with stock characters and a boring villain with a scribbled-on-the-back-of-a-postage-stamp McGuffin of a "scheme". The film builds zero tension, never giving a sense of a nation under siege, or looming catastrophe, and as for plot holes I give you the question: why, when the lights in the tunnel go out, don't the drivers the villain intends to crash into McClane switch on their headlamps? Or: why is McClane carrying so much weaponry when he goes to pick up Justin Long? There are unanswered questions in ULTIMATUM, and probably larger ones (although I forgive them because I find that the film works so well in what it sets out to do, which is to be an edge-of-seat action thriller), but DIE HARD 4.0 ain't exactly a masterpiece of watertight or intelligent scripting.
And I'm supposed to believe that BOURNE ULTIMATUM was a masterpiece of intelligent screenwriting?
No, you're not, and that's not my point - I've already conceded that ULTIMATUM has unanswered questions (plot holes), and that they're probably larger than those in DIE HARD 4.0. I've always said that the Bourne films have lapses in logic, and feature unbelievable situations, and I'd never say that one of ULTIMATUM's strengths is its script. (For instance, ULTIMATUM suffers from a howlingly blatant and redundant scene of "Explaining Things For Viewers Who Haven't Seen The Earlier Films", namely Bourne's trip to see Marie's brother, which is an unconvincing episode that doesn't propel the story forward one iota and just hangs there like the dead weight it is.)
However, the difference is that ULTIMATUM, as I see it, is so brilliantly-made and well-acted that it rises above a frankly flawed and mediocre screenplay. In other words, the behind-the-camera talent (Greengrass, cinematographer Oliver Wood, composer John Powell, etc.) and actors do a splendid job with a sub-par script. However, with DIE HARD 4.0, not only is the script sub-par - everything else is, too. While both films had less-than-wonderful scripts, one was made with incredible flair and fizzes with tremendous energy, while the other was made with a half-baked air of "Will this do?" and consequently just about passes muster as, at best, a so-so rainy afternoon rental.
But we'll have to disagree on this one (and I know I'm in a minority with my dislike of DIE HARD 4.0., which most people seem to think is pretty good).