So before I begin, I'm going to use this design for my own BIonicle G3 regardless of whether or not it is used for TTV's G3.
So here's what I'm thinking for the Island:
I did this on a tablet with a Note taking app. Please don't judge.
But, yeah, this is not the best, but I'm proud of it!
The Region of Oceans: AKA the Water region/Ga-Koro. This was thee first one I drew, so it's the worst out of the bunch. If you want to see better artwork, go see @Oomatu's topics (Seriously, if you've not seen them, what are you doing?)
The Region of Frost:Name's subject to change, but basically there's a bunch of snowy mountains, with perhaps some glaciers floating in the sea. I imagine the Matoran here strive to feel the most connected to Mata Nui, so they isolate themselves to do so.
The Region of Quakes: Subject to change, again. Just some black mouintains with patches of vegetation/crops on top of them; there would be caves in the mountains, where the matoran live, as well.
The Region of Magma:Bunch of mountains and a few volcanoes here and there. Matoran here are warriors, Mercenaries, guards, etc. They strive to maintain there warrior status all their life.
The Region of Deserts: Here, stone matoran labor in mines, in what I picture as those giant termite mound things one would see in Africa (if that's not an accurate description, then I'm sorry)
The Region of Skies:I picture the giant mounds of floating ground in the sky, actually being held up by one or multiple giant trees. I took inspiration from the Lego Group's Idea for the Jungle region, as they wanted a similar concept (but never did/showed it). The Matoran would also have a gliding sports thing, which I will go more in depth to, later.
So yeah. There's a brief overview.