What must novel dialogue. . . really be and do? It must be pointed, intentional, relevant. It must crystallize situation. It must express character. It must advance plot. During dialogue, the characters confront one another. The confrontation is in itself an occasion. Each one of these occasions, throughout the novel, is unique.
The great thing about the stage is that you have a structured month-long rehearsal period where you're going in every day. You have to have lots of run-throughs with theater because there are no second takes in front of a live audience.