See, the issue with that is that it sounds like a great deal of other franchises out there. There's nothing inherently engaging about it - if you're already interested in that kind of story, sure, but otherwise there's nothing to make you take a second glance. And it's far from unique - you could arguably apply the same description to Chima, even (although I wouldn't ) .
If I had to pitch Bionicle's concept in a sentence, I'd say "Imagine if the entire universe was the inside of a giant robot's body, and you realize you're actually the white blood cells who are supposed to fight off an evil disease."
That gets attention. And don't just take my word for it - Faber has repeatedly stated that he only had to pitch a single image (the robot's head under the island) to get approval for the concept. The Ninjago premise doesn't have that same hook.
That's not to say you need a hook that effective to be good - plenty of successful stories that I can think of (say, Star Wars) would actually struggle to get such an intriguing, condensed idea. It's one of Bionicle's strongest points as both a thematic factor and a narrative - and frankly, I don't think it would be Bionicle without that notion driving it (controversial statement, perhaps, but if you disagree lets talk about it )
You could argue that the sentence I gave doesn't encompass everything that makes Bionicle, well, Bionicle, but it's the thematic core that drives the entire story (arguably moreso in my mind than ideas even like Kanohi masks, or elemental powers) and it's probably the single most important thing any reboot would have to consider in some way (perhaps with a radical change of some sort to avoid people predicting it? But to ditch it entirely is almost to start from scratch, which is what G2 did).
Oh, don't worry, I don't watch much TV either. I've seen enough to know that I don't want to see much more, unless it's really good. I, too, haven't seen either of those shows - I'd consider TLA, because it sounds kind of cool, but Gravity Falls is kind of... nah, thanks (and unless I'm mistaken, isn't it like a blatant comedy, to the point of almost being the TV version of Literary Nonsense [the genre]? That's not a great comparison for Bionicle ) .
The Lego Movie people do parody. And they do it well. Which is why the Ninjago movie failed.
The original Lego Movie was kind of just a parody of... like, everything. There were some elements that you could almost go so far as to call satirical, even, although to define the whole movie as that would be a huge disservice as to the scope of humor they use.
And Batman worked because they were spoofing off Batman, one of the most recognized pop culture characters of the last few decades.
But Ninjago was a disaster not because they "changed" it from the show (again, "The Lego Batman Movie" was a completely original take on the character; almost a reboot, if you will. So that's not the issue.). The Ninjago Movie struggled simply because Ninjago isn't big enough to support a parody. That's not to say it's not big enough for a movie, but parody in particular demands a familiarity with the source material, which in this case is a disaster for a multitude of reasons:
- Many people don't know Ninjago at all
- Many who do don't know much beyond "it's Ninja" - stuff like the Lloyd/Garmadon relationship and robot Zane would have just seemed arbitrary and weird to them
- Those who are familiar with the show (and don't get me wrong, they are just as crucial an audience, if not moreso) tend to be, like big fans of it, and so when the company that makes their favourite TV show also makes it's breakout movie for said show a parody of that show, it makes sense that the hardcore fans cheesed because they know people won't get the jokes, and they're like "why couldn't you just do the story".
I personally found it really funny, if less so than the other movies, because I'm familiar enough with Ninjago to know the basic story beats (at least, the ones by then. I couldn't tell you anything about the last few years) but I'm also not invested enough in it where I'm upset to see it made fun of (I make fun of it regularly, lol ). So stuff like the "Your element is... Green!" and "I got bit by a snake, that's why I have four arms" had me in hysterics. But I'm in a very small minority of people who know a lot about Ninjago without actually being a fan, although as the show drags on and on I suspect that number has since increased.
For those people to do a Bionicle movie would be a similar disaster, arguably worse - because the fans are dying to see it get a proper story, and a parody (while I'd love it) is not great for a struggling franchise (or even a successful, but non-ubiquitous one like Ninjago) because while, say, with Batman, the fans know "oh, these guys are fans too and we're laughing at the stuff only fans get" with the other two it comes across almost as a mockery of your line because the movie is no longer laughing with you, but at you, which is much much less pleasant.
(And that's why I personally enjoyed the Ninjago movie, because I often laugh at Ninjago )