Well, it is certainly good to hear that Mass. has dropped that oppressive policy/law.
As for English Common Law, many States such as Florida have adopted what is called, The Castle Doctrine, I do not know if that is "officially" what it is referred to or not, but it merely states, "A Man's (or Woman's) Home is their Castle..." Very simple and effective.
I don't care what someone is doing in your home, I don't care if it is night or day, I don't care if they have a weapon visible or not. You should be able to neutralize them on the spot for you never know what they have in their pocket or under wraps, you never know who is behind them or possibly behind you (that you missed) while you are dealing with the one in front.
Life is not a game, and there are a lot of high-thinking people that would disagree with me, call me bloodthirsty or murderous. It is simply not true. It is called survival. If someone brings you violence, they have brought it to you. Even on the street.
Does that mean you kill anyone that is in your way? Hell no, but it means you do not bargain, guess or play parlor games.
Out of pure practicality, you should not involve yourself in stupid squabbles engage road ragers or be involved in that yourself. You should try to de-escalate if there is time, and time is a precious commodity in this game. You should try to get the hell out of the situation if at all possible without resorting to violence. Because even if you succeed in putting the person down, even if you do not get dragged through Court, Civil or Criminal, that person still has friends, associates and family, and through Court Documents, the will know where you live.
Which brings us full circle again as to why it is sometimes best to walk away if you live in a major city. Your attacker(s) will be able to get a lot of information on you.
There are no easy answers.