Wait a minute, Archimedes dear, we're not talking about WW2 and/or the current British way of fighting. I'm talking about fighting to win.
>>1. The cannon does not need to be 30mm or above - whether it's a 20, 25, 27 or 30mm weapon it'll still be handy. This has been demonstrated on numerous occasions in Afghanistan and Iraq respectively since OEF and OIF began. There's little evidence to suggest that troops in contact have responded to a strafing run by moaning that the gun being used isn't big enough.
No, strafing the ground is an imprecise art. You need 30mm to have big enough explosive rounds to effectively wipe out ground personnel dodging between buildings in urban areas. 30mm gives you around 4m radius of death and destruction. Besides you want your rounds able to penetrate a few walls. Remember, we're not in a slow Spitfire strafing trains, we're talking about anti-personnel and the occassional vehicle.
>>2. You do not require an all PGM suite for modern CAS. Again, there is much evidence from theatre where unguided ordnance has been successfully employed in CAS - both bombs and rockets (CRV7).
Yes, absolutely you need PGMs. The Americans found that you would expend the entire load of unguided rockets easily on a few individuals or an enemy car. With guided ones you can take out a car per rocket, actually more cost effective given the fewer munitions expended and the fewer aircraft needed. Unguided rockets have been successfully used yes but then Dunkirk is considered a successful operation too.
>>3. US rockets can be fitted with a form of laser guidance, but they do not all have it as you might infer from LM's post. I'm not sure whether the capability has reached the front line yet, or whether testing is still ongoing.
It is already in use.
>>100-series Hawk would probably be adequate for some tasks, but remember that it would almost certainly need to carry two fuel tanks underwing, leaving it with three pylons for weapons. You could have either the gun or a designator pod, but not both, and the weapons that could be carried on the outboard wing pylons would be limited compared to the range that could be carried on, say, a GR7.
UK currently does not have a good CAS platform. The Typhoon is too precious, the Hawk is too light and the Tornado does not have all-weather loiter and survelliance capabilities.