MiG, of course, was no stranger to canards, having tried them from 1945...
http://www.aviastar.org/air/russia/mig-8.php
http://www.aviastar.org/air/russia/mig-8.php
None of the Western aircraft quoted had the Ye8 canards. The really inovative aspect of the Ye8 was using two small canards to improve the handling of delta winged fighters.
Apart from that, it would be much easier to fit more advanced radars on it than on the MiG21.
MiG, of course, was no stranger to canards, having tried them from 1945...
There were some supersonic developments proposed of the Gnat but unfortunately Mr Petter, Follands chief designer, would not consider making any changes to his design to accommodate the RAF; things got so bad that procurement staff would go to extreme lengths to avoid him.
The USAF have always wanted somthing bigger than the F5E as they wanted a) more range (and/or) b) more payload c) better radar than could be fitted into something the size of an F5 in the 60's. By the late 70's, radars were much more compact and capable, however what really killed the F20 was that if if had been bought by the USAF, NATO or other friendly countries it would have reduced the total F16 buy and therefore increased the Falcons unit cost. The other issue was that the F20 wing was too highly loaded and suffered from high induced drag in sustained turns, it really needed a bigger wing which was offered to the Swedes who then opted to build the Grippen instead.
Someone actually suggested that the Germans could have bought the whole F20 program for peanuts and avoided getting mixed up with the Eurofighter program, which was more plane than the Lufwaffe wanted anyway. They actually argued for a smaller aircraft than Typhoon and came up with a design quite close to that used in the X31 program. It would also have avoided all the German foot dragging which delayed the program and ran up costs for the other partners.
Have you ever noticed the similarity between the Ye-8 and the Chengdu J7-MF? It would appear to morph into the J-10 in a more conventional canard/delta configuration, losing the tail stabilizer. Also, the Ye-8 didn't pack a gun.
I think it would depend on the timescale, if you are looking at the Chinese building a version in the 70's then they would rely on indigenous manufacture for avionics and propulsion. It is unlikely they would be able to source engines from the West as the only countries making military engines are the US, UK and France with most other countries making engines (like Sweden, Japan etc) building under licence. In the 80's and 90's things open up a lot, it would be easier to get agreement to sell both engines and avionics to the PRC, at least until Tianamin square and even then low profile items like avionics would be doable as long as it was done via a third party. The Israeli's are claimed to have sold avionics from the cancelled Lavi fighter project to China along with missile technology.
I think one of the reasons the YE8 was not proceeded with and the Mig 23/27 was, may have been partly the result of the Israeli pre-emptive strike in the 6 day war in 1967. I suspect the Russians wanted better short field performance from their fighters and strike aircraft and also increased loiter time which was more readily achievable with with swing wings.
What kind of aircraft would have served alongside the Ye-8, seeing as it was competing with another aircraft (the future MiG-23) for adoption? Would procurement of both have been an option, or does the Ye-8 becoming the MiG-23 mean that the historical MiG-23 becomes an experimental prototype?
Since it wasn't produced due to "unsolvable problems" (and this is in a country that thought quality control and crew safety were capitalist plots) I'd say that the West will rule the skies as these things drill holes in the ground across Eurasia.