Given Bruce's advancing years, I imagine a DH 6 is already being outlined. Possibly on the back of a napkin.
Frankly, it doesn't matter how good the script and direction is for DH6 as long as Willis is only turning up for the money. Whatever he's done in the last 10 years has had a phoned in and desperately disinterested performance. He was no better in RED in a couple of years ago.