The reason for specialization is that it's usually actually cheaper to produce specialized craft, rather than generalized craft (contingent on all sorts of variables, like manpower, time, and technology). The reason is that the specialized craft can do a given job more effectively, freeing up resources for other specialized craft to do other jobs more effectively. The advantages just keep piling up.
The reasoning behind generalists like the F/A-18 and the new Joint Strike Fighter is that their missions have become a lot more general. Instead of shooting down MiGs or dropping nukes on Moscow, the missions have become fly around in circles for hours, drop a few precision guided munitions on targets as they become available, generally scare the s**t out of would-be defenders, repeat ad nauseum.
There's less of a need these days for best-of-breed dogfighters; it's almost all about delivering bombs and missiles, where there is still a huge amount of diversity in warheads, airframes, and electronics. That's one of the reasons why there's talk about converting the F-22 into an F/A-22 or even a dedicated bomber variant. However, the key to this whole idea is that there's no threat of war with another superpower, and that most of the wars of the future will be against conventionally inferior enemies. Our technology lead is so huge, we don't need to specialize to eke out advantage.
That's part of the reason why there are much fewer basic types of aircraft today than there were after WW2. If you look at those situations where specialization does matter, though, modern aircraft are much more dramatically specialized than those of the past. A bomber like a B-52 or a B-2, designed to drop massive amounts of ordinance over long ranges, is a very different beast from a tactical fighter. Planes designed for close air support like the A-10 and the AC-130 have dramatically different capacities from other types of planes. ECM, jamming, and early warning is usually done by dedicated classes of planes like AWACS, JSTARS, or Prowlers.
Anyway, the point of all this is that the development of specialized craft in the WCP+ area, along with being more visually interesting, IMHO, is, indeed, more effective and perfectly rational. It can be more effective to carry 7 specialized craft instead of 4 generalists (although with a carrier as big as the Midway, you can get away with that much more than on something the size of Cerberus... not that Cerberus seemed to lack for replacements
).