A real life comparison of the Rangers to the modern WC3 carriers would roughly be today's US Navy. Let's assume that we got the big boys, the frontline monsters that are the Nimitz-class carriers. Now CVEs aside, let's take some very old carriers from 60 years ago.
In today's case, a good example would be those old WW2 Essex-class warships. Back in their heyday they were front-line carriers, and definately modern, but compared to the Nimitz-carriers of today, they are obsolete scrap heap. They don't got the hangar space to accomodate a lot of the larger aircraft (last time I checked, an F-14 Tomcat is way larger and heavier then a WW2 era Wildcat or Hellcat or Corsair). Their naval construction is kinda old and their hulls weren't designed to withstand the latest Russian anti-ship missiles complete with 2000 lb warheads (because they were built in WW2, anti-ship missiles didn't exist nor did Russia become a threat yet).
Since they displace roughly 33,000 tons compared to the Nimitz's 95,000 tons, they really can't be classified as heavy fleet carriers anymore. Chances are that if they were pressed into service once again, they would be designated as light or escort carriers. They wouldn't be fit for frontline duty, and certainly be given all the "shit jobs".
Now you can try to modernize the WW2 Essexs into the 21st century, and give it the latest weapons, and radar systems, and all of that, but that can only go so far. The hangar space still can't accommodate a lot of Hornets and Tomcats because the carrier was built to carry smaller WW2 fighters, not modern jet propelled aircraft 60 years into the future. The hull is still kinda weak, and a few modern missiles will deep six it in no time. It's an obsolete carrier, a second-string, the freshmen team compared to the varsity team. The bottom of the barrel.
The Nimitz carriers are the WC3 fleet/heavy carriers, the Essex's are the Rangers.
