What is needed to make it happen? Simple - crack on and order the bloody things!! I've been involved on the fringes with this thing off and on since 1994 and have seen the thing progress from ST(S) via smart procurement to the current iteration of the design. There are an awful lot of things one could improve in the design (putting cats & arrester gear in for a kick off) as it stands, but frankly as long as its a big deck, with plenty of F44 and mag capacity, it can be incrementally improved once in service.
The problem appears to be that no-one is in charge! Some people in town are nominally i/c the requirement, whereas there's another gentleman in ABW who is i/c the technical and build issues. A senior gentleman is alo nominally i/c of delivery, but appears to have no staff, budget or power to make things happen.
The biggest risk to the project is inertia. It ain't going to get any cheaper (and frankly isn't that expensive compared with a number of other projects - Typhoon, FRES, DII, FSTA), so the old smaller is cheaper arguments should be shelved once and for all. Thankfully, the industry team and the IPT seem to have come to the sensible conclusion that small is pointless. The CVS do a great job of banging off a ten-ship mission twice a day, but struggle to do much more than that due to their lack of deck area and servicing points.
CDP just needs to take a deep breath and get Reid to approve the Manufacture contract. I know the current uncertainty about JCA doesn't help, but at the end of the day "if you build it, they will come". Ideally, "they" would be a combination of F35C, E2D and (what would be really nice) some low-time S3B from the boneyard for COD, tanking, ASuW / ASW and anything else you could think of. If we decide that we can't live without the access to F35 software etc, then at least there is a fallback (Rafale), rather than GR9 for the STOVL variant. I know the support arguments will rage on and on, but ultimately that is do-able, its jsut another embuggerance to deal with.
Rant off, over.