I really like your setup for Mechagodzilla, a man made alpha titan used to control the monsters to do our bidding, and that's how I think it will be in the film. This is something I would love to see in another Monsterverse movie, but I don't think Mechagodzilla in general will work within GvK.
I do like your idea, but in a movie titled "Godzilla vs Kong," I would like the movie to live up to that title, with the entire plot revolving around Godzilla and Kong's feud. A subplot concerning a machanical kaiju who becomes the main antoganist towards the end would take away from the concept of cinema's most iconic monsters battling each other (and I just overall don't fancy the idea of a team up).
Ultimately, I would never ever put Mechagodzilla in my film if I were making GvK, but perhaps the makers have found a way to fit him in without creating a messy, bumpy subplot (fingers crossed).
Don't get me wrong, this is a great idea, but I would like to see it in another film, not GvK.
"What’s so great about discovery? It’s a violent, penetrative act that scars what it explores. What you call discovery, I call the rape of the natural world."
— Dr. Ian Malcolm, Jurassic Park (1993)
