Could be. Increased clouds without an increase in water-vapor level (hard to get, but comic rays or dust could do it) will lower the temperature, I think. Increased water-vapor without clouds, possible at lower dew-points, should increase temperature.
I basically agree with your conclusions above. What I have been having trouble finding out though is if an increase in normal clouds is positive or negative forcing for temperature. It may be that over water they decrease the temperature and over land they increase the temperature because of the relative albedo effects of the ocean compared to land.
It may be that increasing the size of the forests contributes to global warming : ) because the vegetation absorbs the radiation.