For an average Airforce yes, but F-22 was not designed for an average airforce alone. Russia and China are also in the equation while designing it.
The problem is RCS of F-22 is classified. Even the much publicized "marble" is still not reliable enough because it doesn't give the radar bands, nor does it specify what is the size of the marble
What size marble do you want although the marble size is irrelevant. lol
As you know, RCS of fighters is very different in different radar bands. F-22 is stealthy, but how stealthy, no one knows except for a few. Don't be surprised if the "0.5 calibre barret" F-22 shows up on an Russian or Chinese AWACS/GCI operating on low bands.
RCS depends on -
#Shape
#Materials
#Radar frequency/wavelength
#Position of the aircraft w.r.t the radar beam(different sides of the aircraft have different RCS)
#Ordinance(if carried on the outside)
It might be difficult to shoot down because for accurate tracking for the deployment of weapons, high frequency radar bands are required(the ones mounted on fighters), but detection is a different area.
I think the marble thing is for X-band or Ku-band, since this is the radar band used by fighter planes and BVR missiles. Who knows. Like I said its classified.
The lower the band gets, the higher the RCS hence greater the chance of detection. You can say why not straight away use the lower bands on fighters, but the problem is the lower the band, tracking accuracy for missile launch becomes a causality and also the antennae/dish size increases. But that doesn't stop a stealth aircraft from detection and nominal tracking by a GCI radar or an Awacs and vectoring fighters in that direction, or alerting them of an Raptor in their midst. Radar Bands -
The lower bands are to the left of X band.
The first designation is from IEEE, and the second is from Nato.
Then add in the whole EW, Decoys, Towed Decoys, Countermeasures, Jammers, this becomes more complicated than it is. It's better to be safe than sorry. It is better to have Maneuverability, HMS, short range missiles, and Guns than be sorry later for not having them. Like I said, 'these countries develop & mass-produce fighters & weapons keeping in mind of going to a possible war with Russia(a country which has full blown (EW)capabilities at its disposal backed up by its military-industrial complex), they are not designed for countries like Syria or Libya or Iraq or Afghanistan or Panama or any other pathetic third world country for that matter, but eventually end up fighting these poor bastards instead of the enemy it was originally designed for!'
There was also a reported kill by Growler on an F-22 was it not? Growler, a non-stealthy F-18 variant, but built for EW.
http://www.defence.pk/forums/military-forum/47873-growler-power-ea-18g-boasts-f-22-kill.html