Would be great to have a wind/flow/water current generator in the Physics model.
Basic: Constant flow across entire stage, with option for intensity ( like horizontal gravity )
Medium: Use a shape tool to outline/mask area affected by the flow and add direction
Advanced: Use shape tool to draw path of flow. e.g. You draw a winding river, you overlay the flow path over the river, everything that drops into the river follows the path.
Of course, I have no idea how hard this would be to implement but if it was available, it would be cool.
Maybe Hype 4.0?