Actually for me this is so much more convenient, dyslexia makes giant docs so hard for me to get through, but this is perfect.
Anyways, I’m to my thoughts:
First off, love your basic idea on how elements develops, however I do have one issue: air. Personally, I think the development of air should be based on altitude. I’m a huge fan of @Oomatu’s design for Le-Wahi and the idea of a floating village makes perfect sense to me. Now I understand that there are some issues of physics when it comes to floatong mountains, however, such things can be easily explained with megnetics (ok maybe “easily” is a stretch but you get the point). And with the knowledge that matoran are made of protodermis which is not to my knowledge magnetic, this explanation would pose no issue.
Moving into the secondary elements I want to start with a formative experience for gravity: falling off a cliff. Ok, I know, it’s stupid, and honestly I’m mostly joking, but it is an intense experience with gravity.
Now on a more serious note: psionics. I find your take on psionics intriguing, however I disagree on almost every note except one: it is a pseudo element. Don’t get me wrong, your argument is sound, assuming that matoran brains function like human brains, but I have to ask: why would they? A human brain is organic, and functions with electric signals and hormones that react with the organic brain, but as you said: the matoran brain is crystalline. Which begs the question: how does a matoran brain work? I of course have a theory (otherwise this would be a waste of time). I think that matoran brains function in a very crystalline way, using high frequency resonances. This would mean the thoughts and actions of every matoran is broadcast outwards in a sonic spectrum too high for even themselves to hear. So how would someone become a matoran of psionics? Much as you described: lots, and lots of meditation. The way I see it, matoran looking to master psionics would have to meditate in order to push to the side everything else in the world so they can hear the faint sound of thoughts whizzing through the air. A sideffect of this would be the loss of their own element as they push even that aside in the pursuit of psionics, this why it would be a pseudo element. Now the question: how does it work? Well, like I said, thought functions on resonances, so a matoran that has gained the power of psionics would be broadcasting thoughts in order to create resonances in others minds, targeting individuals would be functionally possible given that everyones mind resonates at a slightly different frequency, based on how their crystalline brains formed, this family members would resonate at similar frequencies etcetera, etcetera. In order to create something like a mind blast, a matoran of psionics would simply have to broadcast white noise, causing chaos and confusion in the targets mind. Now one might argue that this idea is insane because anyone could become a matoran of psionics, but I’d argue that that’s not a problem given the sheer amount of meditation that would be required to accomplish it. You’d have to not only learn the frequency of your mind, but how to alter it to resonate with others minds, and that would be no small feat. There would be however one element that would be predisposed to psionics, and that would of course be the incredibly rare matoran of Sonics. Their sensitivity to sound would make learning to hear and understand the resonances of thought much easier, and thus they would be predisposed to learning psionics. But those are just my thoughts on the matter.
One of the main things I miss about the Bionicle Retold project is getting to ramble on in voice calls with other crazy technical Bionicle fans