This would not be the conclusion of a friend of mine who flies the F-16 for the Air Force. Radar, stealth, and weapons systems considerations are more important than dogfighting ability.
LOL. First off, "theoretical air-to-air performance" doesn't mean just turn performance, it's the entire weapon system (radar, missile, airframe, pilot). The PAK AF should not only be able to out-turn the F35 but it will be faster and carry a more capable, longer range weapon system. But you do raise an interesting point about our priorities and what will matter.
Which is/are the most important factors for a fighter has always been up for debate and the debate continues even now. Your friend would be foolish to make such a blanket statement because he doesn't know where, when, and how the airplane will be used. It's like the old argument of whether the F14 was better than the F15. The F15 turns better at altitude but the worm turns at low alt. The F15 is almost as fast as the F14 was but the Tomcat carried a better missile. But, in the end, these arguments really don't matter if you're operating off an aircraft carrier then the F15 is completely blown away. So, as usual in fighter comparison the correct answer is "it depends".
Remember when speed and radar missiles were "more important" than dogfighting? Turning and burning were "so 1940's" and we ended up with the Century series of lead sleds with no guns and no ACM training and that didn't work out great. Radar IS important but then there are radar countermeasures. Stealth IS great but then there are stealth countermeasures (and we don't fly just at night). Advanced weapon systems with BVR missiles ARE great but then there are Positive ID and other very restrictive Rules of Engagement which frequently deny BVR. The real answer to which of these capabilities are more important depends on the mission, tactical environment and ROE.
Consider a future war with F22 and F35's against the PAK AF. All of their weapon systems will be extremely limited, in fact almost useless so guess what that leads to? In some ways, we could be back to WWII or Korea, fighting in an almost strictly visual arena. Wouldn't that be interesting? You can bet your little booties that maneuverability will matter.