At the end of the day, you either accept that STOVL aircraft might have a use (and around 30 years ago we found out just how useful they could be) or you don't.
The STOVL was not justified 30 years ago. If we still had the real aircraft carrier ARK ROYAL (not a "through deck cruiser") with Phantoms, Buccaneers, Gannets, et al we probably would never have lost SHEFFIELD, COVENTRY, ARDENT, ANTELOPE, SIR GALAHAD and ATLANTIC CONVEYOR. The air power projection of the 60/70s ARK ROYAL would have allowed for a proper AD screen backed up by AEW and a proper strike-attack plan on the Argentine forces - not the "make do" harrassment and patchy air defence provided by the small Harrier force.
Don't get me wrong, for what they were the SHars and GR3s did a magnificent job - but if you ask those on the ships above or involved in the ground campaign what they would rather have had it would not be a STOVL aircraft.
Oh, and as for Kandahar's runway length, there are non-STOVL types out there that could work from the minimum operating strip (MOS) using Pneumatic Arresting Gear (ie. cables) to land and their vast amount of SEP to get airborne. For example, a Super Hornet can get off unassisted on ~400m and then use the arrestor gear for any aborted take offs in the overrun.
The B Word