To start, let me establish that I was a HUGE fan of both Bill & Ted 1 and 2. I absolutely LOVED them as a kid. However, this 3rd one was just absolutely horrible imo. Here's some of the many reasons why:
* The biggest plot hole is that people from the future, who can and have time traveled, didn't know it was Bill & Ted's kids instead of them??? That in and of itself is completely inane! They are from the future! There are obviously historical records, witnesses, iPhones and other recording devices that recorded it!!! With how many people witness what goes on, how could time-traveling humans from the future possibly NOT know that it was their kids instead of them?! The notion that they somehow confused who did it in and of itself completely turned me off from this movie. I don't know about other fans, but I personally wanted to see Bill and Ted succeed!
* Tying into that, in the first two, we clearly see they eventually build a band, that the band includes their wives, death, and them. They make albums (doesn't Rufus even ask them to sign it for his kid?), they are renown all over the universe for saving it, yet their kids were NEVER mentioned in the first two?! Why was there absolutely NO mention of it from Rufus? The first two clearly firmly established it was them who did it, but then now, the people from the future suddenly know absolutely nothing of the past, everything they believed was apparently wrong, the band shifts to their kids, who just slop something together at the last minute, which just happens to unite the universe? I mean come on, wth...
* The movie is generally depressing. Bill and Ted have been failures all their lives, their whole purpose of their life slipping through their fingers, and then they jump to futures where they also failed? Just so sad to see. And then on top of that, there is a robot sent from the future to kill Bill and Ted just in case? They go from practically worshiping them in the first movie, to trying to kill them?! There were TONS of other ways they could've explored the probable realities and come up with a better solution.
* Their children having the same exact mannerisms, phrases, etc. of Bill and Ted was WAY too over the top. Were these kids isolated in the basement all their lives? How were they NOT exposed to other people that actually talked and acted normal?! Plus, their acting was HORRIBLE. I didn't even believe them as human beings, let alone Bill and Ted's kids.
* They milked WAY too much of the content of the original movies. I mean the same phrases repeated, all for nostalgia. I get some of that is nice, but it was WAY too much rehashed.
When I first heard about them making a 3rd Bill & Ted, I teared up a little. I was SO excited. But this dumpster fire of a movie was complete trash imo. The first two were funny and playful. This one was depressing, repetitive, unbelievable in every way, and overall horrible. Honestly, I feel like the writers just slopped some trash together simply to milk the original two. Shameless. They ripped the heart and soul out of two amazing movies, all for an extra buck.