So to summarise SSSETOWTF - the requirements doc doesn't say we want to carry bigger weapons and go further so they are pointless capabilities??
I would suggest the doc was written and the F-35B designed so they fitted each other. Ask any (non-harrier) pilot if he would like the ability to carry bigger weapons if needed and go significantly further (or presumably loiter longer) and I think that he would prefer that option.
Also as just this once said, there's little point in breaking through a sophisticated IADS only to discover that those damn uncooperative bad guys buried their important kit in tgts that a 500lb bomb can't get to.
Personally I'm going with Orca's point about single-service agendas and SSSETOWTF's point about the F-35B being very ease to land - the change is clearly another RAF plot to get rid of the FJ element of the FAA.
What's the plan with all those F-18 exchanges now? Straight home, I guess, the cost couldn't possibly be justified in the current climate?!?