Froch is a giant compared to GGG. And we don't know GGGs full potential yet as we do with Froch.
With that said, people shouldn't sleep on Golovkins amateur boxing background. He's got some serious impressive wins there, and while it's not EXACTLY the same as pro fighting it says something. The correlation between a great amateur = great pro is there more often than it's not.
And his style definitely caters better to pro than amateur boxing.
Mark my words, Golovkin will be the middleweight kingpin for the next 5 years.