How would you handle Evil Axl?

As desperate as I am for anew Mega Man X game I always get stuck on the story, I truly have no idea what they'd do.

We already got Evil Zero, an idea that should've been an easy slam dunk, and yet they screwed it up. But with Axl I just don't know what would be interesting with him turning evil, what would make it narratively important.

One thing I know for sure is that I don't want it to be Lumine posessing Axl (even though that was probably the original intention). I'd rather it just be a vague corruption, with Axl picking up Lumine's general ideals.

So would you want? Should Axl be the main villain? Should he still be playable but have a new mechanic linked to what Lumine did to him?