It's all good with the lengthy analysis and appreciated. But in essence the answer lies simply in the different doctrines used by the two blocs in aircraft design. For eg, The West has always looked for killing without being seen since the 60;s, keeping out of danger.However, with missile technology not living up to its hype in the early years this was not possible. So they found themselves faced with agile east bloc aircraft for which they had to develop tactics and then eventually fighters to counter them. Then again, they took the upper hand until the current generation of Russian jets emerged. However, by this time electronics and missiles systems had matured enough to give them the edge in these long range combat scenario's. The Israeli's for eg, understand that command of the electronic spectrum is much more important rather than extreme dogfights. Their approach to modern air combat is possible one of the best. Using a combination of advanced electronics, high off boresight missiles and BVR they maintain their edge against any possible adversary. The Russians picked this up in the early 80's when they realized they could not match the US pound for pound in command of the electronic spectrum, but they could inflict damage by forcing themselves into a close fight and then using high off boresight missiles to get a kill and offset superior training and tactics. That philosophy survives to this day. The PAK-FA is possibly never going to be as stealthy as the F-35 or F-22. but its designed to be invisible long enough so that it can come charging in and then engage in the close fight.
However, the Americans have moved further ahead with the F-35. They realize that strike fighters will be hunted by threats such as the PAK-FA and Su-35. So the only way past them is to be able to "out-sensor" them. To see them first, to have all of them see the enemy first. And use superior information processing to create a faster and better strategy to kill them. The F-35 with its EOTS allows the pilot to engage and kill with his head alone. It is well shielded enough in the IR and Electronic spectrum so that it may survive any initial attacks. Perhaps in the concept of David and Goliath.. it does not look to match enemy aircraft pound for pound..or dagger for dagger.. it looks to strike the death blow first. Which is why it is still a better aircraft than the PAK-FA despite the latter being much more impressive in aerodynamic performance on paper. With the F-22 though, the PAK-FA may very well face slaughter on a 1 for 1 numbers engagement.
However, the PAK-FA's enemies aren't the F-35 and F-22. Its the export enemy..the J-10, the J-11..the F-16 and so on. It is designed to beat those fighters at their game with an easy margin. I dont see the FGFA as being any better than the MKI is to the Su-30K canard demonstrator. i.e it is still limited by the basic airframe and design and hence wont be much more stealthier or more manoeuvrable.However, it will have the advantage in electronics.. and it will be interesting to see how those will stack up to what is in the J-20 or J-31. It's main prey however, will be J-10's, J-11's,JF-17's and F-16s for quite a while.
