Hi MK,
To fly high and fast with fuel, combat load, you will fly higher and faster depending on a very large number of parameters. We could try to look at a few. One for example is the engine thrust available on the JF-17. Compare that to the thrust available on a MKI or even an F-16. And you may find an issue.
To fly high and fast, drag is another important factor, as are certain aerodynamic characteristics such as wing loading, which would greatly impact your ability to maneuver effectively at altitude.
If everyone would build a competent modern air superiority platform with a single RD-33 (RD-93), the world of aircombat would be very simple and all these high powered aircraft that cost so much more, would be redundant in many ways.
Imagine the scenario of "shoot and scoot" as was being discussed. 4 Su-30MKI enter Pakistani airspace and is confronted with 4 JF-17s. The MKI are higher, are faster. They fire 4 BVR missiles each at the Thunders, at greater range than the JF-17s can respond. Now the JF-17s are on the back foot and trying to evade a very large number of missiles coming at them.
Even if they manage to fire a few BVRs, these would be so far away and at such energy states that the MKI would be able to turn away, go on a race track, and come back if they chose, to fire of a few more BVRs (or if they have to go home, for whatever reason, maybe to play with their kids, they can just go home).
Now if they chose to come back after a racetrack circle to avoid the JF-17's bvr, they would find the JF-17s at a great disadvantage, possibly without BVR missiles to boot. The JF-17s would most likely scoot for base, and be replaced by another flight of JF-17s. Doing so would not be impossible but operationally difficult as all this would hapen in a matter of a minutes.
This means PAF has to have a much higher tempo of operations, or more aircraft at any given point. Or F-16s that can more or less match the MKI in such kinds of combat.
Or better yet a combination of F-16s and JF-17s, which is how the PAF possibly envisioned it. Such a strategy would essentially negate the IAF advantage.
Here are some other points against the JF-17's BVR capability:
1. It has lousy acceleration through the Mach. This is crucial in a BVR optimized fighter
B. For any combination of weapon baseline SSPK and range, the farther you shoot the more misses you will have. Most MRAAMs are at best, a 2 point missile and with only 2 onboard, any shot past NEZ (6-8nm = .85 SSPK, 10-12nm = .5SSPK, 12-15nm = .35 SSPK) (these numbers are for the AMRAAM, SD-10 is equivalent?)
Where you have an effective 12-15nm AIM-120 pole, that is poor. Where you while 35-40nm T3 or Meteor RamAAM, are more useful. MKI could potentially field such LRAAM a lot sooner than PAF.
And without having to burner your fuel reserve to nothing in getting supersonic to make the cutoff.