Drones might be the way to go, but can they carry the amount of ordinance needed for CAS? They might not currently have the capability to fly "swarms" of drones at the moment.
The whole thing is just strange. They want CAS stuff, but the A10 is an old platform, can't operate off amphibious assault ships like STOVL planes, and will likely only see action against low-tech forces these days. If you need a jet for CAS due to more advanced anti-aircraft systems, sure, the F35B could fill that role, but then why not just use carrier-based assets or land-based assets instead? The branches of the military can't keep treating the taxpayer like a never ending pocketbook and duplicating each others services within their own.
But if they need a non-drone CAS plane for COIN-type operations or against low-tech enemies, it just seems like the more economical and just as practical option would be a modern turbo-prop, like a Super Tacano or Beechcraft AT-6, or a modern OV-10 (Boeing has proposed an OV-10X). Armchair engineering here, but I bet something like one of those could operate off the smaller decks of the amphibious assault ships (googling shows some pictures of OV-10s on Tarawa-class ships) that the Marines use.