My feelings on the idea are also quite mixed. Perhaps a compromise would help. Reduce the speed limits on most of the city roads but the major arterials---routes in/out and across the city---should be raised. I don't think people will tolerate snake speeds in vehicles that are designed to safely travel at far greater speeds.
Don't forget that when you are riding in your car, you can set a good example for other motorists by using a reasonable speed when it is called for, treating cyclists with courtesy and giving them (you) their proper space, etc. And if you go the speed limit, in many cases people behind you have no choice but to reduce their speed to yours as well.
roughstuff