Let’s get back on topic, shall we? I’d say this answer has been adequately answered.
Right, hence, headcanon. ![]()
for instance, they would probably have fixed that little bug in Mata Nui’s creature creation systems. You know, made it so that he didn’t create shadow beings that could theoretically end him?
Well, in defense of my own kind,
Makuta were not technically created as shadow beings, they chose to get rid of their light on their own accord later, which I think that would be beyond Great Being’s influence at that point.
But I do agree that, as you said, it could have been better. 
One could say that. But then again, this topic has some pretty great discussion so I’m gonna leave it open for now.
Well, this has gotten off theme
Back on topic, Vakama made the mask but didnt know the powers. Maybe also he had never seen a great huna before. I havent heard of any other toa to wear one
But each mask comes from a specific Kanoka, and the matoran on Mata Nui knew what power their masks would have.
I wonder how many matoran swapped out their original mask for one that they would like to have the power of if they ever became a toa? Maybe they wore masks shaped like their favorite toa? 
Good I found this topic, as this question bugs me off lately. Toa Metru had a mask maker in their team, he should know what power has any mask. Although, Toa Metru masks were mostly in Noble form, perhaps they were some special cases for wearing Great versions.
But the issue still stands. Like, there was no moment when, let’s say Whenua came up to Vakama and was like
”Hey, Vakama, what is my mask and what does it do?”
”You should have Ruru and it should give you night vision.”
Pretty sure the entirety of the story confirms this with how Matoran are constantly presented as having somewhat naive, childish personalities (not all of the time, but the 2001-2003 story really does this for most Matoran, as do the movies).