I haven't seen Bonucci since he joined Milan, but I guess he didn't turned into s#$^ in one season. Having seen Rugani play for us, he doesn't seem to look so reliable as Bonucci did in his last 2 seasons with us. Having said that, I can really understand us selling Rugani and bringing in a better CB (Godin / Bonucci) so we'll upgrade our CB department for around 2 years at least. Sure, Rugani can grow just like Bon did, but the thing is we can't afford his mistakes now and he'll only grow if he plays and makes his mistakes. When Bonucci was doing the same thing we werern't signing a player for 100M+ and we were not CL contenders.
I'm not as mush advocating a Bonucci return, but more a Rugani sale for a good price.