It's all about the money.
In time, it stands to reason that there will likely be a Russian-produced rival to the Raptor, as well as one or more Western European offerings.
The point of building such a fighter, is primarily to compete in the same market for exportable front-line fighter planes. The economic issue is far more serious to Moscow than building a fighter that can actually defend Russia's airspace from the F/A-22. The Kremlin probably isn't very concerned about defending Russia from the US Air Force- they are worried about China, India, and several dozen other nations possibly choosing to buy a better, ( and much more expensive ) plane from the US, or the EU. They are a fledgling capitalist democracy, and they realize that they must export something (anything) that is on a par with the Raptor in order to maintian credability in the global arms market. It's quite a tough predicament for them to be in, actually, and the market is going to become even more competitive as time goes on. China is likely going to develop it's own 5th gen. fighter at some point in the near future, further drying up any potential sales to Russia's current number-one customer.
But it is far too early for Russia to be banking on future arms deals, as the US has (publically) led in this field for decades. There are still details about the Raptor's abilties that are not in the public domain. And it's likely that the inevitable future upgrades to the Raptor will ensure that it remains as the world's top rated air-superiority fighter. As long as the Raptor is on top, there will only be two parties to be in: Those nations that have the Raptor, and those that wish they had the Raptor. Those that can't afford the F/A-22, will seek to buy anything that is believed to be almost as good, from the lowest possible bidder. Needless to say, the Russian MFI ( MiG 1.42, etc etc ) was not the Raptor-killer that they hoped it would be. Maybe this new Russian attempt might actually produce something that performs as advertised.
Everyone else is simply playing catch up as best they can, and probably when they finally get the fifth gen. fighter they so badly desire, the US will have already moved on to it's sixth generation platforms, anyway. ( If they havent already begun to do so. Their R&D seems to be about 20-30 years ahead of what is released to the rest of the world. We must assume that much is always going on behind the scenes in their super-secret "black budget" programs. )
Or, they could even change the rules of the game altogether as they did by developing and producing front-line "stealth" platforms to begin with.
The only way to get ahead of them, will be to figure out what technologies will likely replace 5th gen. and pour enough money into production in order to dominate the market before the Americans do.
Personally, I believe that this 5th generation is likely to be the end of manned fighter airacraft, and the future is likely to be dominated by the UCAV.
If this is the case, the train has already been hijacked by the US again- they are already well into advanced R&D on various UAV/UCAV programs, and seem to be preparing for full-rate production, well ahead of everyone else. once again, just how far ahead they are is anyone's guess, but it will likely be decades before we are discussing Russia's answer to America's first generation UCAV.
So, what will be the most likely counter to swarms of stealth UCAVs? Probably air-borne laser platforms, I guess.
And there too, the Americans are already far out in front.