As I said before, I don't think Biden will be the Democratic nominee. Even if he is, having a VP from the same region, northeast as Warren would be doesn't give the ticket regional balance. Delaware and Massachusetts are locks for whomever the Democrats nominate. Why not someone from a swing state as VP? At least a different region of the country.
I would say with Biden, his VP should be someone much younger. Warren is 69, Biden 76, talk about an old foggie ticket. Although I like Joe, always have. I'd rather see a fresh young face win the nomination instead of Joe or Warren, Sanders also. I'm not a democrat so my druthers mean nothing. I'd like to point out some history, tired old political faces from the northeast haven done so good for the democrats. Dukakis Massachusetts, Johns Kerry, Massachusetts, Hillary Clinton New York. Young faces from other regions have, Jimmy Carter Georgia, Bill Clinton Arkansas, Obama Illinois.
JFK is the last Democrat from the northeast to win, 1960. Back then the northeast was liberal Rockefeller Republican country and JFK was a fresh young face. Just something to think about.