Valid points, Vietnam was a bigger war because it was a spread-out jungle war whereas Iraq was concentrated in urban areas so there were fewer men needed- and less losses- which reduced the public outrage.
But neither war was necessary IMHO- and the aftermath of Iraq will be much worse- being right in the middle of the Middle-East- it has enormous foreigh policy ramifications for years to come. For example- in the long run I think it will increase terrorism against the US because a whole new generation of young Arabs are growing up filled with hatred for the US.