Gums - I don't think the question is will the 35 do a job - but more is it all it could have been?
I think the A and C model have been seriously aerodynamically compromised by the VSTOL B model. - think the very wide shoulders for the lift fan and the wave drag that implies.
The lack of acceleration is a result of this.
I think the 35 was supposed to be a bit of everything to everyone - and now kind of hides as a attack aircraft with limited A2A.
Partly this is from the US services eroding their great position in the 80s - with a very capable high low mix
USAF F-15 and F-16
and USN F-14 and F/A-18
But the USAF didn't get enough F-22 to replace the eagles - so now the F-35 has to take up more slack as the lo part of the mix
and the USN have never replaced the F-14 so they are going to field to aircraft that are essentially both the low mix - F-18E and F-35.
Yes there are lots of good gizmos on the F-35 (expensive and late they may be) but what if you had fitted them on your A-7 instead?
How much worse would that have been than the F-35?
I certainly think the avionics could have been fitted to a better airframe (not compromised by a VSTOL model) and ended with a better and cheaper result.
And certainly the cheap economy of scale hasn't delivered with the F-35.