A-7 Corsair II versus A-4 Skyhawk

Which was the better light attack aircraft for U.S. carriers in the 60s-80s?

It seems like the A-7 Corsair should have been better in all respects:

– Newer design – almost 10 years newer
– F-8 Crusader pedigree! (Including dedicated pylons for AAMs)
– Larger aircraft with more payload
– Replaced the A-4 aboard the supercarriers, relegating the A-4 to the smaller light attack carriers (modified Essex)

Yet history seems to have smiled more upon the A-4:
– The A-4 was sold to many more countries
– The A-4 earned an excellent reputation as an attack aircraft and even as an agressor, and seems to have been more popular among its pilots than the A-7
– The A-4 seems to have aged better than the A-7: received more upgrades (see Singapour and Israel), and outlasted the A-7 in U.S. service
– The A-7 was said to be underpowered and had to sacrifice internal fuel load to carry its maximum external payload

So was the A-7 really an improvement over the A-4? Could the Skyhawk have served successfully without replacement (but with upgrades) until the arrival of the F/A-18?