I'd have to agree with @Fershizzledizzle.
Matoro's death was one of the most impactful moments in Bionicle history, and diminishing the consequences by not really making the death a death would have made it feel less real and important.
It is a really neat concept, I like the idea of having to become a new Great Spirit, but it wouldn't feel right.
I also feel it wouldn't fit with Matoro's character, or the set-up we had in '06 and '07. Matoro barely believed he was cut out to be a Toa, so I don't think he'd be comfortable with taking the responsibility of becoming the literal god of his friends. '06 and '07 also had plenty of foreshadows to Matoro's fate: his sacrifice in the staircase to the Mask of Life (showing he was always more willing to die for his friends), his Mask of Spirit, and his Mask of Reanimation, two masks related to death in some manner.
I could see this version happening if he was still an Inika, though. Maybe he discovers Mata Nui's true form from the Mask of Life, then uses his Mask of Spirit to inhabit the Great Spirit Robot.