I think specializing does help w/ maintaining proficiency and ability w/in a limited scope, but I don't think that's an official policy. In some cases, Reserve squadrons don't have the newest gear, so they can't do all the missions that the REGNAV squadrons can (LAMPS has this issue). In other cases, you have much more experienced guys who can focus on specific mission areas and do them very well, so why have them waste the limited time of reservists to be jack of all trades (reserve aggressor squadrons, for example).
As Uncle Fester said, squadrons like -4/84 are their own weird animal and because they've been both specialized as well as busy, they're not even exclusively reserve anymore. I'm not sure if -85 will take the same shape when they get back up to speed.
As Uncle Fester said, squadrons like -4/84 are their own weird animal and because they've been both specialized as well as busy, they're not even exclusively reserve anymore. I'm not sure if -85 will take the same shape when they get back up to speed.