after doing some reading on the subject, it seems I was wrong that a fleet of small carriers can do all the jobs of super-carriers. it depends on what kind of missions the navy is expected to perform.
If you want carriers for power projection. ie, the kind of mission like what NATO did to Libya. You want big supercarriers. Nimitz size is probably optimal, the smallest you can get away with is probably the new QE carriers. Small carriers simply can't carry the fuel and munitions necessary to sustain high sortie rate over an extended campaign.
However, if the navy is only expected to perform sea control missions or sea denial, a fleet of small carriers may just be the answer.