Die Hard has become such an interesting franchise: there's no way that anyone who got into Die Hard with the first film truly enjoys the later ones. Like, at all. But they make a bunch of money, so somebody is watching this horse crap upon which the holy Die Hard moniker is being slapped.
Fox has run the series into the ground - Die Hard At Chernobyl was just a fucking monstrosity - but that doesn't mean they're giving up! If they couldn't make us care about John McClane Jr (and since they cast Jai Courteney in the role, no, they could not make us care), they're going back to the start. No, not a reboot of Die Hard. Worse. A prequel to Die Hard.
Yes, Len Wiseman is coming on board to direct Die Hard 6, which will be a prequel featuring Bruce Willis in bookend pieces, reminiscing about his time as a cop in 1979 on the gritty streets of New York City. There are a lot of reasons why this is a terrible idea (prequel and Len Wiseman are more than enough reasons), but the worst thing about this is that Die Hard 6 is almost guaranteed to undercut Die Hard.
Here's why, and here's what Fox hasn't understood about Die Hard since With A Vengeance: John McClane is a regular dude. When he gets up to his neck in terrorists in Die Hard that is a totally unique, over-the-top event in his life. He was a normal beat cop before that - taking down street level thugs at best, probably securing crime scenes and walking a beat most of the time. He didn't have epic adventures before Nakatomi Plaza; that's the basis for why we like McClane in that movie - he's a regular guy in over his head! By having a prequel where something big happens (and a studio isn't signing off on this to make a prequel where John McClane does a couple of routine arrests) the series will be retroactively ruining the first film.
Of course you could always just not watch Die Hard With An Origin, but you know that you'll hear about it and you'll catch pieces of it on cable and the next time you watch Die Hard - the classic, unbeatable original - you'll have this little thing in the back of your head telling you "Oh, remember that time in 1979 when John McClane saved the president and diverted a nuke from New York City to the middle of the Atlantic in a giant bomber plane?"
It's worth noting that the great Howard Chaykin already wrote a Die Hard prequel in Boom Studios' comic Die Hard: Year One. That is much more street level and probably more interesting than anything Len Wiseman can come up with.