It's a good idea but Wall Street is too nebulous and broad to go after, in my opinion. I'd suggest occupying the Federal Reserve instead seeing as they're in charge of the monetary policy for the USA. I also notice political organizations trying to co-opt Occupy, MoveOn.org for instance. I am more interested in the wider Occupy movement across the world, I wonder what may come from this aside from sending a message that people seem to have had enough.
It's similar to the Tea Party, started by the Ron Paul campaign and grassroots, now mostly co-opted and changed, some for the better, some for the worse. (Herman Cain as a tea partier, for instance, is a little strange being a Federal Reserve chairman (?) in the 1990s).
No movement starts and solves things in one night though, politics is like a game of subterfuge, so we'll see what the end results will be.