Yes the mask corrupted him, but I still want him to be evil in the end. I'm not exactly a fan of bad-guys turning good (as at times it feels a bit unrealistic). It's nice that Ninjago did that with Garmaddon, but we don't need that for BIONICLE.
Think about the similarities Ninjago and BIONICLE have already.
*Heroes with elemental powers.
*Skull bad guys
The last thing we need is for Makuta to turn good. If that happens, BIONICLE will look like a knock-off on Ninjago in terms of story, and we don't want people thinking that.
I already tried to explain BIONICLE's new story to a kid before, and he said it sounded too much like Ninjago. BIONICLE needs it's differences!