You'd think that the current UK CAS setup in Afghanistan is failing, judging from the frequency with which people snipe at it! So, rather than have 3rd parties pontificate about the various shortcomings of the GR4 / Reaper combination, let's hear from any of the following:
a) A mover who thinks that GR4's apochryphal "massive logistics tail" is preventing other vital supplies from reaching KAF
b) A JTAC who has 'winchestered' a Reaper or both elements of a GR4 formation and has been unable to obtain further CAS support almost immediately
c) A JTAC who would rather have unguided rockets back, instead of a laser-guided missile and a gun
d) A JTAC who finds it difficult to communicate with a WSO or sensor operator who is 100% focussed on the ground situation, and would rather go back to talking to a single pilot who is simultaneously monitoring his targeting pod picture, keeping an eye on his junior wingman and trying to avoid all the UAVs? (I think it's fair to say that 100% of a WSO's capacity trumps 25% of a single pilot's capacity - just!)
If no-one answers, can we assume that our CAS/CCA provision (not forgetting the AH64!) is up to the task and find a different argument for keeping our ship-based jumping bean?
Eureka! Ship-based! That's what'll save it! ermm...
I would argue that the American experience in Afghanistan shows that you don't need specialised CAS aircraft. The busy, highly kinetic northern taskings are filled almost exclusively by F15E and F16 out of Bagram. Any complaints about the service they provide? Why would the US replace their flexible, capable aircraft with a one-trick pony such as a Super Tucano? (the answer is that it wouldn't be a replacement, but an addition!)