The Harrier is the most potent and capable CAS aircraft ever used in combat.
Now that is utter and complete bollocks!
The productivity you get from a reservist is way below what you would get from a full-time service pilot working part-time, for many reasons. Understand that almost ALL reservist pilots (we have several) have airline jobs, limiting their availability and therefore their usefullness. Also, reservists cannot be sent into Operational theatres at the drop of a hat - they have to be called up by Parliament. Doing so would almost certainly cost an airline pilot his job - you cannot simply hop from one aircraft type to another, you have to maintain currency on a type to be able to fly it. Operational flying ALWAYS brings with it short or no-notice committments. In short, a non-starter.
Perhaps you have forgotten about the US Air National Guard for a starter. More bollocks!