An interesting question!!
Especially so when one considers that the U.S funded the Buccaneer's development via U.S Government / military aid (....sorry I have forgotten the correct title of the funding program). Not to mention that with this funding came very transparent and frequent U.S Navy appraisal and inspections. But I assume that you might already be aware of this fact
Would the Buccaneer have been somewhat to big and heavy a design?
The US did briefly evaluate the Buccaneer (in fact, there was a USN pilot on secondment as part of the RN 700Z Flight evaluators), but the A-6 was selected for that requirement. The Bucc was never a contender for VA(L), AFAIK.
PS: If the Bucc had been adopted by the USN, the process would have been something like the USAF adoption of Canberra. A US builder would have been found and a lot of redesign would have followed. At a minimum, there would have been US engines and avionics.
The Allison TF41 was a licence-built Spey, I believe - so would it have been simple to replace the Buccaneer's RR Speys? And might the Buccaneer subsequently have gone through a similarly extensive programme of development to the B-57? EW and reconnaissance versions...?
The attack aircraft "Corsair" II. From the Vietnam War to Desert Storm That's what I wrote. I would be happy to be of service!
('Штурмовик "Корсар" II. От Вьетнамской войны до "Бури в пустыне" That's what I wrote. Я был бы счастлив быть полезным!)