When people say get rid of zoning, generally what they mean is to move to an intensity based zoning scheme. i.e. One where the zone indicates the "maximum" type

When people say get rid of zoning, generally what they mean is to move to an intensity based zoning scheme. i.e. One where the zone indicates the "maximum" type of construction that may be built. i.e. in low rise residential zones you can only build low rise housing and small shops, in high rise residential you can still build low rise residential, in commercial you can build large commercial spaces but you can still build residential, and in "light industrial" zones you can build non-hazardous industrial structures but you can still build everything else. However for full blown industrial you can only build industrial due to the hazards. In practice that looks a lot like just getting rid of zoning entirely with the exception that traffic management works out a little better and actually dangerous industrial sites are still kept away from everything else.