Parabasis: Shakespeare the Pragmatist:
Shakespeare wrote his plays for specific actors. Having recently directed a play written for the actors who were in it, I can testify that there is no way to do this without it fundamentally shaping the eventual script. I was at a talk that Simon McBurney gave about his Measure for Measure where he discussed researching the original production to the best of his ability, which included finding out who played various roles and how they were known in the theater community at the time. According to him, the Duke was played by an actor known for funny voices and impressions. This lead him to notice that the Duke speaks differently depending on who he's talking to, and the contrasts are so sharp as to render the character almost incoherent. Now what does that say about the character, about the attitudes towards power in the play? McBurney's production would eventually contain multimedia elements, abstract choreography and all the other trappings he's known for, but it started with originalist research.
Part of what makes Shakespeare great is that he addressed himself to the specifics of the needs of his troupe and his audience while simultaneously creating lasting art. Sometimes I think we focus on the latter and not the former, when it's the integration of the two that makes him so special.