there were too many new “lame” characters who popped up in Godfather 3 that didn't fit in, instead of cultivating the "existing previous characters"
eg: Sonny and Sandra's son/s, Michael's son and even Connie's son/s as power struggle schemers instead of inventing the new character Vincent,
I think they wanted to explore Michael's quest for social legitimacy with Vincent's quest for birth legitimacy, so it wouldn't work with the other kids.
