This "everything MUST be explained" attitude is one thing that bothers me about the BIONICLE community. It was really painfully apparent when Hero Factory was new and a lot of BIONICLE fans had to wrack their brains to understand how and why the robots of the Hero Factory universe came to exist (short answer: it doesn't matter) and how and why they have thoughts and feelings (short answer: they just do).If you were telling a story set on Earth in the present day, you wouldn't start with the Big Bang, the time of the dinosaurs, the birth of Jesus, or even World War II unless those things were important to your story. You wouldn't even have to tell about your protagonist's childhood if it didn't become relevant. These things would give you more information, sure, but in many cases they simply wouldn't be a part of the story you initially set out to tell.
If I was telling a story on Earth in the present day, my audience knows about all of those things, because they are on Earth in the present day. Therefore, when approaching a story set on the Earth in the present day, the audience naturally makes a series of assumptions about the setting, the weather, the culture, and so on because they live here. They assume that apples fall from trees and hit people on the head, that people wear clothes and have childhoods and don't come from nowhere, and even that that iPad I just referred to is the same one your friend saw in Target last week.
With Bionicle, nearly all of that is pretty much scrapped. We are looking at an entirely different universe, with entirely different people (biomechanical beings), entirely different culture (worshiping the Great Spirit, Toa Code, etc), entirely different technology (elemental powers), and even entirely different physics (stretch, to be sure, but I haven't seen any EP around here just yet).
Therefore, the audience demands an explanation for all this eccentric and unusual stuff. They don't ask for one about stories set on Earth, because they know what they are. The audience wants to understand, and they want that explanation in terms of the reality they know. I think that is perfectly reasonable.
Similarly, if there were a movie of the 2006 story, you could probably omit almost all of the events of BIONICLE Legends #4: Legacy of Evil, focusing only on the important bits like where the Piraka's Antidermis supply came from. If there were a movie of the 2007 story, you could probably omit the events of the Toa Nuva Blog, which happened alongside the Toa Mahri's quest but scarcely ever affected it directly. If there were a movie of the 2008 story, you could probably omit Mazeka and Vultraz's side-story, which was hardly relevant to anything in the grand scheme of things, and most of the other serials as well.All things considered, almost all of the events of the 2009 story other than those covered in BIONICLE: The Legend Reborn were irrelevant to the events of that movie. They were relevant to their own individual stories, but in the grand scheme of things they were just lengthy exposition that helped set the stage for Mata Nui's arrival (and in the meantime, promote the sets that didn't yet have a movie to serve as their backbone)
Agreed here, though. Except for the part of Mazeka's and Vultraz's side-story being irrelevant, although I'll grant you that it shouldn't be in a 2008 movie.
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Yes, that's right, 2008 should just have one big movie. All that background material could have been delegated to the books where it belonged - the movie should focus on the Toa Nuva battle, and maybe a little bit on the Teridax-in-the Core Processor fights. (To some degree I think they actually did that with the Advance/Ghost movie for the year, but hey could have expanded it without harm IMO.)
2006 and 2007 would have been trickier to do a movie for. I think 2006 could have been done through a series of TV shorts, but the films would be so disparate that only ardent fans would be able to link it together. For example, you could have one focusing on the Piraka, culminating in the Toa Nuva battle. Then one focusing on Jaller and his journey through Karzanhi, then focus on the Toa Inika for a few more episodes culminating in the battle with Vezon and the mask's descent. I think it would be good as an episodic format, simply because there was so much disparate stuff happening.
2007...not sure. Again, lots of stuff happening, so it makes sense to do episodes, but there would be fewer of them.
The problem with the above is that there wouldn't be enough episodes, and nobody wants to run a TV show for only two years. So they didn't.