I don't see why that core can't be Eastern Conference elite team. You've got a defensive anchor, a true gunner, a two way wing player, and a dynamic pg. The key is to get them all to gel, which it looks like they're slowly doing.
Something to keep in mind: Arenas and Nash were both guys considered to be not worth keeping around. Of course, they went on to become two of the best pgs in the NBA. Those four guys could do an awful lot with the right coach and the right system.
Get a new coach, and they'll be in much better shape.
As for Vincent, he's gone.