The advatntages of a VSTOL/STOVL carrier is that you don't always have to launch into the wind,with the ski jump,
That is simply not true, unless the plane is lifting off in VTOL. If that is the case, the mission load be negligible and close to useless. Even for STOVL , you will need the carrier to be moving , preferably into the wind, so that the relative wind over the deck is higher by that much , for eg, if take off speed in still air is 150knots and carrier is steaming at 25 knots, into the wind , which is blowing at 5 knots , the effective take off speed , relative to deck will be 120knots and the take off run will be that much less.. Okay, you can argue that for a given load, the STOL run will be less than for a conventional aircraft. But that doesnt matter. For a given aircraft, ,if you are not steaming into the wind, the relative wind speed drops and even for a STOL run, you will take off with a far less load than you would otherwise will be capable off . In plain speak , if ship was not traveling, you will have to accelerate to full take off speed of 150 knots and not 120 knots in the limited deck length and you cant do that with full load and you will have to shed weight!.
plus launching,or rather taking off and recovery by STOVL is far easier and safer than recovery by arrester wires
The accident rate of the Harrier is far higher than an aircraft like F18 etc with arrested recovery. And that is primarily because of the problem of engine failure in hover (primarily exhaust ingestion into intake) and in case of engine failure, it falls like a stone (it is not flying anymore remember?).
And more importantly, the bring back load will be far less than a conventional plane. The bring back load in a VTOL will be limited by the engine thrust in hover mode, which will have to support the weight of the plane in addition to the load!.
All in all VTOL has huge compromises.. The advantage is it greater flexibililty in terms of tactical deployment (dont have carriers ?) well, a short underprepared strip will do!
The Brits just want a follow up to the Harrier and that is why they are pushing it. More than the RN, it is the RAF and USMC which will have far greater use of the Harrier, especially in close support roles. It is really not the primary fighting arm when facing a very capable enemy. It is primarily meant to intimidate the smaller coastal states with no or minimal air power (like Argentina for instance). The far sensible thing for the brits to do is to go the French way, adopt cats like the French are going to do for the same carriers and BUY THE RAFALE
..oops, that will be a huge loss of face and honor if they have to buy a plane from the Frogs.. Okay, buy the CTOL version of F-35, the "C" version instead !