Complete and total spoilers (although nothing unexpected happens at any point in the film so don't worry about it):
The original Independence Day was very much a product of its time. It represented the ultimate in Hollywood summer blockbuster glory. The money was all up on the screen and you got what you paid for. Yes, it was very bombastic and mindlessly jingoistic in the true American tradition but it got away with it because it had an appealing sense of character - it was charming.
Independence Day had inimitable personalities. Nobody can play Will Smith like Will Smith can, Jeff Goldblum is literally irreplaceable. Randy Quaid is method acting crazy and Judd Hirsch is a constant thorn in everyone's side. Robert Loggia and James Rebhorn are the crotchety old guard and Bill Pullman is the optimistic young Bobby Kennedy. On paper, these characters are stock archetypes but they are brought to life by actors with personality (not even taking into account any actual acting ability, which is not entirely necessary in this kind of film). Even Brent Spiner and Harvey Fierstein make the most of their small but memorable roles.
Resurgence, on the other hand, has Chiselled White Guy, Heroic Black Guy, Pretty White Girl, Dorky White Guy, and Token Chinese Girl. That's what they were on the drawing board, it's what they were in the script, and it's what they are on screen. I've no idea who they are and I've already forgotten everything about them. Even the African Warlord manages to be completely anonymous and inexplicably has an English accent.
Without the character to hold it together, the contrived plot and lazy storytelling really start to fall apart. The set up itself is intriguing enough: twenty years have passed and the human race is benefiting from the scientific progress that was allowed by the the abundance of alien technology. But then this is never really explored beyond cool laser guns and planes that don't have to worry about aerodynamics.
For some reason all the major new cast are ten years too young to have any kind of interesting character traits. This seems to be because they desperately want to tie them in to the original film so the children of everyone in the first film now all know each other and all went to school together or something. There are relationships, good and bad, that are given the most cursory development needed to keep the story moving. The plotting and progress of these characters is so contrived that it actually feels like a parody of overblown Hollywood films that need to rush through a pointless love story to get to the next action scene.
The ham-fisted attempts to try and bring in some emotional resonance into the personal stories is downright laughable. Interestingly, there is a legitimate attempt at portraying a homosexual relationship that is not defined or validated by its homosexual nature, but is simply a relationship that happens to be between two men. Even in 2016, this is notable in its rarity in a Hollywood blockbuster. Ironically, this is the relationship that manages to evoke the only genuine emotional response from the film, perhaps because it was more underplayed than the lead love story, which essentially boiled down to, "Shucks, I'm gonna finish my service and go home and marry my best gal and get that nice house with the picket fence because that's what momma would have wanted."
If we were supposed to learn anything from the original Independence Day, it was the concept of brain over brawn. When blasting something out of the sky doesn't work, you have to come up with something a bit more subtle. Guerrilla tactics and putting the greater good over the individual. The message of Resurgence seems to be to shoot first and ask questions later. And when that doesn't work just keep shooting until it does. The original had a great deal of internal conflict between the pacifist leaning Goldblum and the militaristic side of Loggia, with Pullman's diplomat playing the mediator. Here there is no such conflict, with everyone entirely in agreement that we must kill everything in sight by shooting it with laser cannons.
The one thing that Resurgence does manage to emulate from the original Independence Day is its ability to preach a message of unity and tolerance while still managing to be condescendingly racist in the way that only white people can be.
As a sequel, it fails on every level. As a stand-alone film, it is at best a mediocre piece of Hollywood nonsense that has nothing original or special to offer. On the technical side it is solid with the spaceship battles being spectacular enough to satisfy those that like that sort of thing.
If Independence Day was a spectacular July 4th fireworks display then Resurgence is like a New Year's celebration in Rhyl. You can give it all the flash-bang you want, but at the end of the day, you're still in fucking Rhyl.