Also, just to add to this, the F-35 contains a 27 mm cannon, with a firerate of 1800 rounds per minute. Definately sufficial to damage most objects an A-10 is fit for. Also, lets not forget the much greatly advanced technology uses in the JSF, which can probably engage an enemy threat from a further distance, etc.
Also remember how the F-35 is a multirole figher, not specific for any one thing, and therefore will never be as 'dedicated' in the ground attack role.
Although both aircraft MUST be respected for their own individual strenghts, the F-35 is a next gen fighter, and will, most likely, be just as good as the A-10 was, possibly better. (The allowance of newer, updated and more powerful weapon systems which can only be used with the F-35's technology...)
Gripen and EF-2000 are nice, both Multirole again. This is nice, but often means the a/c is not as good in one thing or the other...
All nice aircraft though!