Everyone knows about the good old “what’s the difference between earth and stone” question but what about the other elements?
Sound is basically vibration of air so theoretically speaking, a Toa of Air should also be able to control acoustic waves.
Same goes for plasma and fire. In Bionicle, plasma is basically a super hot liquid which apparently is to hot for Toa of fire to control but I see this just as a lazy explanation.
Magnetism, Iron and gravity could pass under the umbrella of earth-based powers.
Air and lighting was already represented together (Energy Slizer).
Psionic as an elemental power was always kind of a stretch to me. Most of the psionic powers could be easily allocate to Kanohis (such as Matatu).
Having more elements might seem cool and makes the world richer but I think in Bionicle case it causes crippling overspecialization.
Having less elements with wider range of applications is in my opinion better than having over a dozen of elements that overlaps one another.
What do you think?
Personally, I would never have added the secondary elements at all. Makes elemental powers a little more clean.
True, that’s why I’m advocating that secondary elements could be merged with thier primary counter parts. So we can still enjoy those powers but they don’t bloat up elemental charts.
I propose.
Fire+plasma
Earth+stone+Iron+gravity+magnetism
Air+lighting+sound
Water
Plantlife
Ice
Remove Psionic
Light and shadow are moral elements so they should stay unchanged.
This way we still got six elemets but with more diverse powers.
I prefer a more limited form of elemental power to create some amount of balance.
I wouldn’t give air access to sound, though I can appreciate the logic there. I would remove gravity, electricity, magnetism, and true plantlife control.
Gravity is a big one for me, because it’s basically unbeatable in virtually all combat situations. You’re better of poisoning the user or somehow or killing them in their sleep than fighting them.
I should add that ice and water may as well be the same, but you could in-world make ice a sub-discipline of water control that requires specialized training.
You could argue that Ice is less about Ice and more about cold. So it’s not as much as control over Ice as much it’s the abillity to lower a temperature of certain objects and environment. The same can be said about:
fire (rasing temperature),
water (control of liquids)
Air (control of gases)
Earth/stone (control of solid matter)
Being able to control any solid matter is pretty absurd though.
Edit: Also given the mystical elements of Bionicle, I have a preference for mystical interpretation of the elements over a more scientifically adherent one. i.e ATLA.
I think it should be limited to only inorganic materials. So you couldn’t just rapture your opponents organs on a whim. Also that would prevent you from controlling plants and such. You could also argue that the refined material such as metals would be much harder to control and manipulate while more natural elements such as soil and rocks will be easier to conjure and control.
The problem is how much of the Bionicle species’ bodies can be defined as organic.
Most of the species in Matoran universe propably follow the 85/15 rule (85% mechanical, 15 organic)
Then again a mechanical parts of the being could still be considered partialy organic, for example such having cellural structure kind of how cybertronians are described in some Transformers continuities.
If you prefer more arcane explanation, you could say that mechanical parts of MU beings are imbued with thier life force and are considered alive beacuse of this.
Where does that rule come from?
Assuming it’s correct, 85% gives a lot for an Earth Toa to control.
This is what would make most sense to me – something close to how it works in avatar, where the elements are more broad, and skilled characters would be able to access more advanced abilities:
Fire + plasma
Water + ice + mud
Air + sound
Rock + metal + sand + crystal
Lightning, plantlife, psionics, gravity, and magnetism, would be unique abilities used by a one-off toa, dark hunter, oomn member, or some other character
But alas, if I ever were to create a bionicle story or animation, I doubt I’d tamper with the elements much. The elements are just too iconic to me. 
Then again, I’m not saying that Toa of Earth should be able to control ALL of the solid matter. Just everything thay comes from the ground, earth, rock, mud, crystals, ores, metal and so forth
@Atobe_Brick I once heard a rumor that there was only suppose to be 4 Toa for each of the classic elements but designers were informed that line will consist out of SIX figures so they added white and black sets later in production.
Then again this is only a rumor I heard years ago.
Edited for Double Post - BioKnight
Earth+stone, iron+magnetism, and gravity is a completely different thing. Maybe delete gravity.
Joining air and lightning is kinda dumb, they are clearly two different elements. And sound is basically vibration of matter, not just sound. It’s fine been it own element.
I feel like sound is kind of useless as a standalone element, at least compared to the other ones.
Yes sound is vibration of matter but air is the most common medium. Even if traveling through different means, sound can still be cancelled out by other elemental powers ( traveling through water? Can be nullifield by Toa of water. Ground? Toa of earth and Toa of stone).
Air and lighting can work together if you put them under a different name like storm or weather.
But why? Air and lightning works great as different elements. If you want you can combine lightning and magnetism. Creating storm as an element is a bit of a stretch.
Plasma, as I see it, could work like the plasma blasts in Star Wars, while fire is basically a big flamethrower.
I always figured the Great Beings made these guys for practical application rather than combat. From a story perspective it’s easy to define these abilities by their combat-effectiveness but from the standpoint of “this is a huge piece of equipment and Toa are components of it”, It’s more about having nanites with mastery over certain elements (literally) that could get out of hand from time to time.
For clarity I move to leave the element roster unaltered. Although I did give Kinetics some serious consideration back in the day
I guess I could see combining Earth and Stone, but the distinction, whatever it is, is too well ingrained in my understanding of elements to really support it. In regards to other proposed combos:
- I think Magnetism and Iron are both different enough from Earth and from each other to warrant being separate. You could do an “Earth users can manipulate metal through extra training,” or vice versa, but since BIONICLE powersets don’t really expand that way it would be somewhat out of place.
- Air and Sound are very clearly separate in my mind. Sound doesn’t just travel through air, it can also travel through water, earth, and organic materials. The element of Sound is, I guess, really just control over minute kinetics of every material, but it’s certainly not the same as Air. I don’t think a Sound user could reasonably create lift the way Air users do, for instance.
- Lightning is also very different from Air, perhaps more so, as it deals with electricity rather than gases. I wouldn’t group it with any of the other elements
- Plasma is something I always thought was a bit cheap, and could easily be grafted into Fire since it’s just superheated gas.
- I guess using the above reasoning Ice should probably be a subset of Water, but since both are prevalent natural substances I think there’s a case to be made for different powers controlling them. Also I just like them being different. My actual reasoning, if I gave any, would be that Water users can’t control the temperature of the substance–if they can create ice, it’s by pressure freezing, not by temperate-induced phase change. Ice could, maybe, involve other cooled things too. I wonder if Kopaka could control dry ice?
- Psionics is cool. Don’t knock Psionics. =P It also runs the whole gamut of mental powers, which is better than a specialized Kanohi.
- I have no feelings on Plant Life. It doesn’t seem particularly elemental to me, but maybe that’s just me.
- Gravity is highly overpowered and maybe should be nerfed, and I don’t think of it as much of an element either.