One of the things impressive to me about Carlo was that he was basically ready to go almost right out of the box at 20 years old when he first hit the league and was paired with Chara.
I know some people have issues with him because he doesn't go out there and kill guys with his size but I think he doesn't get enough credit when it comes to physicality. He's not overtly aggressive like Peeke but I think he's stronger physically. He plays tough minutes, averages 130 hits/110 blocks a season, and is normally steady and reliable.
Carlo to me is a keeper and when all is said and done, Boston will be lucky that they didn't have to worry about their top 4 right side D for over a decade. GMs around the league would sacrifice their first born child to have that kind of security for one of the most sought after commodities in hockey ( good RHD with size ).