Looks like all of the points have already been hit. Citing revenue figures as success is stupidity, tyranny, or whatever you want to call it(be creative). The idea behind speed limits is to keep people from going so fast they crash. I'll not get into how well it works, that's a whole 'nother issue.
I think that's a site I've been to before. One thing they mention is dubious placement of the cameras, and changes in speed limits and such after they're placed. The two I remember was one that was placed a few meters too far away from the curve or whatever to encourage slowing down, and the other was the speed reduction, I can't remember if it was five or ten MPH, but it was significant.
It seems that Britain, even with all those cameras, has trouble catching the responsible parties even in urban areas. Think about the Texas countryside, and the fact that we have guns. I'd imagine that there'll be a new category of long range shooting opening up if this goes into effect.