"That it would be a mismatch of epic proportions"
It was a mismatch of epic proportions. Mayweather wasn't in any risk at any point, and controlled the match from the beginning.
And saying McGregor is a 'boxing novice' is disingenuous. He's been training in kickboxing and other martial arts for decades. It's not like he just learned how to throw a hook a few months ago.