The only thing they are waiting for on the SU-57 is the new engine. You can't be called even a Pseudo 5th gen fighter unless you can super cruise. It has the avionics and defense package, the manueverability, weapons and more. It's a nasty package that would be hard pressed to be handled by anything other than the F-22. But it does lack super cruise.
Let's take a good look at super cruise. Is it that important? Actually, it's probably not. Okay, you get there faster in Military Power. It uses less gas than in Afterburner. But you are still at Military Power. This isn't how fighters go from point a to point b. They keep the speed down to well below Mach 1 to conserve fuel and then power it up when they enter into combat. Supercruise doesn't extend your range on a fighter one iota unless you have to get there in a hurry in the first place.
If it were that important, there are new engines that are made available for the F-15 that are in the 31K class that would allow the F-15 to supercruise as long as he kept his missile package and external fuel down to a dull roar. They don't see the need of the engine because it gains almost zero to go to it. In order to justify it, they would have to drop fuel and weapons. Or they can leave it alone, get there at Mach .95 in Military Power instead of Mach 1.5 in supercruise and have more weapons and fuel to get the job done.
But the world is fickle. If it can't supercruise it is a bad thing. The F-35 can't supercruise, ergo, it's a POS. Well, it can't but it's still a bad assed bird. And as time goes on, people begin to not place the degree of worry that it can't supercruise on it. I think that just because the SU-57 can't supercruise is keeping it from entering the world stage is just ridiculous. What's sad is, the world is buying their SU-35 which is an older and inferior fighter to the SU-57. In the end, the SU-35 is still an upgraded SU-27, nothing more.