For me this was an exercise in excellent writing and that's always an important beginning. Contrary to most belief in Hollywood, excellent scripts are needed for good movies.
As in the first Die Hard, the whole movie is about getting two people who have become estranged back together. In the Die Hard they blew up a building to get Holly and John together. In this Die Hard they take down all the electronic systems (banks, electricity, etc) in order to get John together with his daughter - who hates her father so much she uses her mothers maiden name as her own last name.
The first Die Hard used that estrangement as the outcome of all the mayhem, the second Die Hard and third Die Hards had to do something else and they weren't nearly as good.... this one goes back to what worked the first time - even making references to the first movie that were hilarious then and remain hilarious now. It's a fascinating continuum.
The other writing rule that this movie carries off spectacularly is: "What happens when your lead character can't grow?" John McClain is already as strong and tough and invincible as he can get. So they bring in a character who can grow, who moves from utterly powerless geek to superhero under John's tutelage. It's an interesting writing trick and I thought they did it well.
Some of the special effects were outrageous and it was hard to suspend disbelief even as it was hard not to enjoy them. The villains were delightful. The humor under the carnage is fun. It was a good movie.