Shump is on the floor playing D in crunch time anyway. Hiding Calderon instead of Larkin is a lateral move at best.
Bargs might be better 1v1 but he might be the only big in the NBA that is worse than Amare in help defense. Any coach worth his salt would exploit either matchup in half court sets.
Melo getting out of his funk is the only thing that will drive this team to better results. His jumper has been
all season and hes settling. Im not sure I buy that "bad offense leads to bad defense." Some of the best defensive teams last year (Indiana, Chicago, Memphis, Charlotte, etc) were below average offensive teams. It comes down to talent on both sides of the floor.