The Distinctive Baritone said: "I do a lot of Shakespeare, as both an actor and a director. When I'm coming up with a "concept" for a production, it's usually while trying to answer the question, "What can I do to best help a modern audience connect to this 400 year old play?" Usually, that involves setting it in a different time and place, or giving it some sort of design aesthetic (summer themed, steampunk, etc.). There's really no reason to do any of Shakespeare's plays in Elizabethan dress, etc. unless perhaps you are doing one of the history plays, or you are purposely doing it as a museum piece a la Mark Rylance's Globe productions.
This approach can also apply to some modern plays - i.e. David Cromer'sOur Town,Ivo Van Hove's...well, anything he directs...
The thing is, this is, I think, much harder to do with musicals. They are just a different animal. Also, althoughSam Mendes' made popular the "seedy"Cabaret,which basically upped the shock value, since blatant sexuality and the horrors of the Holocaust are much more familiar to audiences than they were in the 1966 or whatever - he basically changed the aesthetic of the play, but...the 1930's wasn't that long ago. I'd say for most musicals, unless it takes place before the 20th century, it's probably not old enough yet to warrant a change in time and location. It's just too soon for it to really work for most musicals written over the past seventy years. Give it a couple centuries."
For me, this is the perfect answer!