The F-16 was designed from the outset as a dog-fighter. The moderate sweep of the wings and aspect ratios were ideal for this. The trade-off however, was greater supersonic resistance. The thrust offered by the two engine options on the F-16 is impressive even to this day.
TWR in air combat is about 1.15, ensuring impressive climbing rates and sustained turn rates. As noted, the F-16 sacrificed supersonic performance, not only in its wing design but also in its fixed air intakes. In supersonic flight, engine thrust is lost. While it can reach Mach 2.0, pragmatically it has poor supersonic performance.
While the F-16 sacrificed supersonic performance for subsonic dogfighting, the J-10 did not make the same sacrifice. Thus, while when the F-16 was designed, turning dogfights were what was projected as the bread and butter of air combat, when the J-10 was being designed, the BVR era had arrived (or re-arrived).
The J-10s aerodynamic design, including wing design and inlet design, take this into account. For instance, the J-10 visibly has greater wing sweep and a variable inlet. With the J-10B, a DSI intake. While the J-10B sacrifices maximum theoretical top speeds with its DSI intakes, for all relevant combat speeds, it gives the J-10 superior performance.
Under modern BVR conditions and higher altitude combat, the J-10 is significantly superior to the F-16. This is also reflected in its higher instantaneous turn rates. The Mirage-2000s have been a point of major concern both for the Pakistanis and the Turkish air forces, because of these aerodynamic issues, despite the Mirages weak engines.
The Greeks, who operated both the Mirage 2000 and F-16C considered the F-16 to be better at low altitude, low speed, hard turning fights, and Mirage 2000 to be superior at hi-hi.The F-16 would have to attempt to survive the first merge in an air combat scenario, which becomes increasingly suicidal with high off-bore sight missiles.
BVR further compounds these problems for the F-16s. In previous eras, flying hi and fast was fine, but you often had to come down low to engage a low flying enemy aircraft. Today, that becomes less relevant with longer range BVR missiles and look-down shoot-down capabilities.
The F-16 has also been adding weight over time and attempting to counterbalance this with increased engine thrust. However, since wing area remained the same, maneuverability has been sacrificed. Higher wing loading is particularly detrimental for higher altitude maneuverability. The J-10 on the other hand, has all the wing area it could ever need with a delta canard layout.
The newer block F-16s however, are great for low altitude air-to-ground missions. The high wing loading favors low fliers and the moderate wing sweep helps handling at lower speeds often necessary during ordnance delivery. The J-10 is thus not ideal for the CAS role. However, because of the range and payload advantages, the J-10 can be considered an effective deep striker. CAS was never a pressing need for the PLAAF, and the PAF has the JF-17 which is ideal for that role.