Has this been covered before in this thread: quality of 1L professors and what makes them stand out? I see BU touted their awesome professors and rankings in the Princeton Review, but a cursory glance at faculty at both BU and BC seems to show that they all come from top schools and are extremely qualified. Is the reason we don't hear as much about BC professors is because BU is actively marketing to that effect?
It's funny, I have noticed that BU always goes on and on about how awesome their professors are (the students are oddly defensive about it too). It kinda reminds me of Volvo in the late 90s/early 2000s constantly talking about how great their safety record was. While I'm sure both are true, both are talking in absolute terms, not relative terms.
For whatever reason BC does not market itself to say: ATTENTION: AMAZING PROFESSORS INSIDE!!! Instead they say things like, "IF YOU GO HERE YOU WILL NOT HATE LIFE"...it's just a different marketing strategy based upon different strengths relative to their other strengths.
To answer your question regarding 1L professors, what makes them great is their ability to ensure enthusiasm for the material. Every professor is intelligent and knows the material cold. But the great ones will inspire the students to learn and internalize the law. The great majority of my professors do this, but all of my 1L professors had this ability.
I wish admissions would do a better job on this front and I think they're starting to. In recent years BC nabbed a few smart hires and supposedly made a good pickup in the new dean.