Here, I want to simply discuss and list old elements in Bionicle that will be returning. As more is confirmed, I will add them to the list below. Discuss what you think will make a comeback for Bionicles Reboot!
1: Makuta
2: The Toa Mata (Not official name in the reebot)
3: Gears
4: Dual Functions
5: Mask mechanisms
6: Vahi referenced
7: Mask of Creation
8: "Toa"
9: Elements
Though not teridax by name. I think they’re making makuta a character not a race, like 01-06 
Specifically though, this Makuta is based on Ol’Maky Terry D.
Just saying, the title can get a little misleading. May I suggest changing it to something like “classic story elements in new bionicle”
I’m hoping that they retain the Matoran into Toa aspect, or a version of it.
I think that if they do that, they may lay off on Destiny a little bit. I can see them doing this as a kind of 'Everyone can become a hero," message for one year.
I imagine Light/Takanuva will HAVE to play a role in Bio15 sometime.
I hope not.
It will and you know it.
Anyways, I actually want to keep the protectors and masters different species. Keeps it less confusing for the younger kids. (I actually had some trouble describing it to my friend earlier)
My Nuvaverse story hinges on the idea that the villagers can become Masters, so it would suck if that was not the case.