Here are my thoughts on what the Azm project would look like based on a few strategic options:
Strategic Options 1: Single Englined (WS-15) Vs. Twin engine (WS-13 / WS-17)
The single engined option is actually the more likely option here because:
1. The WS-15 is a far more advanced engine than the WS-13, which is close to an RD-93. WS-15 is a generation ahead.
2. PAF has traditionally preferred a single engined fighter, which is what is ideal for the defensive scenario of defending Pakistan
3. Commonality with a major and to be widely used Chinese engine.
Strategic Option 2: Stealth VS Maneuverability
Stealth is not only expensive, but creates major drag and increase in weight. While the US can burn through it using a very hi-tech engine with the F-35, it still is unable to make the F-35 even equal to an F-16 in maneuverability. Making the false claim now that maneuver is not needed, something that PAF is not likely to agree, given its tradition in air combat.
PAF is looking to replace F-16s. Not develop air superiority over New Delhi. It does not need an F-35. It does LOVE the F-16. PAF basically would naturally want to build the ultimate F-16. Project Azm is most likely going to aim at being just that. Just like JFT was an 80% aim towards an F-16.
If that is correct, PAF will go for a LO design focused on being "the ultimate F-16" with some stealth features. NOT an 80% F-35.
This probably means an RCS of about 0.05 - 0.1 in the front arc.
Since this is a defensive stealth plane, unlike the F-22 and F-35, all-aspect stealth is not needed as much. You are basically designing the stealth to be effective against a frontal enemy fighter.
This in turn means an internal carriage of weapons is not necessary. The Tornado design proved this with semi-recessed carriage of weapons in various tests.
Stealth is 80% design. And Azm would be well ahead of any past such design. With semi-recessed weapons loads, PAF would gain a few key advantages:
1. Major reduction in drag, weight and complexity, due to no internal weapons bay
2. Ability to be both a LO aircraft AND an arsenal plane at the same time.
The WS-15 would provide more thrust than anything any F-16 ever had. With a progressive iteration of the JFT design enlarged and stealthified, we would see a major capability leap over any generation of F-16, while having the following advantages (say over an F-16 Block 52):
1. A faster, more maneuverable aircraft
2. A lower wing loading due to new enlarged design
3. An IRST, AESA radar, better and more powerful ECM and EW
Strategic Option 3: General Design Layout
There are basically three practical options in terms of project Azm's suitability and practicality:
1. Conventional F-16 / JF-17 / F-22 Layout
2. Delta Canard J-10/ J-20
3. Delta Twin-tail YF-23 style
Of these three options, #1 is the most likely given:
1. Low risk design
2. Closest to the F-16 (PAF's fantasy plane)
3. Excellent for commonality, allowing PAF to us Israeli training tactics of providing part of the air-time training on the JF-17 / F-16.
If all of the above reasoning is correct, we will have (under the most likely scenario):
1. A single engined, conventional layout fighter
2. WS-15 engine
3. LO of around 0.05 - 0.1 RCS, mainly for frontal RCS not all aspect
4. Semi-recessed missiles rather than internal weapons bay.
just my thoughts.