The fact that it's something that isn't even hugely relevant today (it's not like it's Star Wars popular or anything) is just an added slap in the face.
You say, "It's not like it's Star Wars popular or anything" like 'Star Wars popular' is something easily attainable. What is Star Wars popular right now besides Star Wars? That aside, it's hugely relevant today. The original movie broke box office records at the time (and still holds the record for an opening weekend box office in August). It pulled in almost $800m worldwide! When my dad (who is 60+) saw it, he said afterwards, "I haven't felt this excited about a movie since the original Star Wars." As others have said, many people think it's up in the top 3 or top 5 movies of the Marvel Cinematic Universe, which is saying something. It's up there with the likes of Iron Man, the Avengers, and (my favorites) the Captain America movies.
Shoot, I don't even show GOTG to my kids, it's so vulgar. And they won't watch the cartoon. Too boring they say. Great! Now we have a ride based on a blah movie's 10th most important character. Lame. Why don't we just retheme the Winnie the Pooh ride to Porkin's Death Star Crash.
Your kids are right. The cartoon isn't very good. But the people involved with the movie (namely James Gunn, the writer and director) aren't involved in any way with the cartoon. Also, if you read the description instead of jumping to conclusions after the first paragraph, you'll see that it's not based on the Collector (10th most important is pretty accurate, good call there). It's more going to be based on Rocket trying to help the other Guardians escape the Collector.
I'm actually very much in favor of this. My DD8 rode ToT two years ago at DHS, but not again since, as it was a terrifying experience for her. She was going to go when we went to DCA last month, and that had a complete melt-down in line, so that she and I had to use the chicken exit. Part of her problem is the name, "Tower of Terror." She likes GotG. Maybe she'll get past her anxiety and actually ride it, now. I myself am not a big fan of droppy rides, but I like GotG enough that I'll go.
My daughter had a similar experience. She was psyched to ride it (she was 6), but the theme actually scared her quite a bit. She was super nervous. She loves screaming on "scary" rides, but on Tower, she was completely silent during the ride, and just looked terrified. When it stopped, she cried. "I don't want to turn into a ghost!" I'm not proud of it, but I laughed pretty hard at that. Even though I explained to her that it's just a story, she vowed to never ride it again. Maybe with this, she will.
Besides that, even, I'm excited for this. It sounds like they've put some real thought into it, and that it's going to capture a lot of what made the movie great. Comedy, action, and a great soundtrack. I'll be sad to see Twilight Zone's theme go away, because it was incredibly immersive and some of the best theming in the park. I get it.