I think some out of the box ideas of utilizing existing space is going to be the real and viable way forward for JF-17 upgrades. There wont be any major redesign or increasing the size type to exercises with the jet at all and definitely no new engines or thrust vectoring etc.
One thing I would like to see in a Block 4 or even later retrofits in existing blocks 1/2/3s is the EW/EECM capabilities enhanced further. There are already many ideas of using under wing weapon pylons to serve with a dual functionality such as
https://www.terma.com/media/105019/two-pager_defense_air_pylon-based_ew_solutions.pdf
Similarly, towed decoys can also be used with pylons and it would mean less tinkering with the tail or its associated brake chute
https://en.wikipedia.org/wiki/AN/ALE-50_towed_decoy_system
With ECM and EW gear, the cooling requirements are going to be a challenge but I don't believe that part is insurmountable.
For the IRST, using a podded system is not only easier, it will also be much faster in fulfilling the requirement, if there is one. Since IRST is primarily a passive A-A detection instrument, hanging it in a podded fashion under a chin intake is not a good idea. That means while the jets with A-G missions might use the Turkish LDP, fighters providing top cover could use the same station for an IRST system.
No need to try and shoe box in a compact solution in an already small air frame that might never get developed or funded.