>>21664530He's not a clone of Doom you jackass.
That's like saying chocolate milk is a clone of me if I came in it, hit blend, froze it and then chizeled it into a vaugely human shape.
Anyway Gerald didn't just use Doom's DNA to create Shadow, in fact he only added it because there were some problems making survive without life support like the Biolizard if I remember right.
As for the crossing canons, the fans don't dictate what the character that is entirely down to the creators of each canon. Just because the movie Mewtwo is the one that people remember doesn't mean it represents the character across every part of the franchise and as for Smash, that's more of a "it's 8-bit cry would sound stupid and making new ones would detract from something else so why not use the anime sounds?" rather than letting the fans make the character.