Also, the Marines want the STOVL F-35B for operation on LHA/LHDs, as well as small island bases with short/limited runways. It's not just the ski-jumping Brits who want that feature.
With that said, you're right that the STOVL capability has added substantial complexity to the airframe.
Naval aviation is of extremely limited utility as a result of a short range. If the fighting starts or moves inland the carrier is mostly useless.
I mean, when has the Harrier ever been the difference between success and failure for a USMC operation? Sure it's nice, but it's also a jet that is very difficult to fly and prone to crashes.
That's why the Navy is so hot to develop the X-47 into something they can deploy.
If refueling aircraft are available then far more capable land-based aircraft should have been used anyway.
As far as when the Harrier has made the difference, well, we haven't fought many pitched battles lately, so it's hard to say. But you can't design a military with the idea you'll never have to fight a pitched battle.
EDIT: By the way, one of the advantages of the F-35B is supposed to be that its design is inherently less crash prone. We'll see.
That's the thing though, by shoehorning that VSTOL requirement into the program, we've made the F35A and F35C significantly worse aircraft. That in turn may mean that we may end up in a more difficult conflict because of the shortcomings of the aircraft.
Sure, if at all possible you want your military to be able to handle all scenarios. But truth is that the budget is not unlimited (as the USSR found out) so you have to distribute your eggs such that you get the best capabilities for the most likely scenarios.
I'm sure the F-35B will be less crash prone than the Harrier as well as more capable. I just don't think the costs justify it.
True, but we're spending less on our military as a percentage of GDP than we have since before WW II. We can afford the F-35B.
[1] http://defensetech.org/2012/06/22/pic-of-the-day-f-35b-shows...