PAF does not have many options to tap into for replacements of its ageing fleet of F-7's and Mirages. Finances, Engine constraints, and Indian influence has closed up most of the options available out there.
Therefore, PAF is doing what it has done best over the years -- making most of what it can get from the market easily and at a lower price tag without embargoes and going for upgraded and up-rated Chinese platforms tailored to its needs.
Replacement of F-7's with JF -17 is ongoing --- with a lower performing engine and avionics suit. However, with an intention to upgrade both in coming years.
Mirages will also be replaced with JFT's but would require a longer range radar and enhanced avionics suit for the deep strike role -- a role that is currently envisaged for Mirage fleet. Furthermore, JFT twin seat version is needed to ensure Nuclear Deep Strike Element within the Mirage fleet can be replaced. Another must for the deep strike role is the availability of air to air refueling capability. all of this and some other capability is either there or being worked upon as we speak.
In essence, New build JFT's increasingly tailored for PAF needs are being weaved into the force. Engine avionics/radar upgrade and use of composites is in the offing or natural progression of a sound platform.
The high end of current PAF fleet is the various blocks of F-16's (76+2). PAF, in my opinion, will keep on adding to it by buying less expensive, second hand A/B's and upgrading them thru MLU/SLEP programs using Turkish expertise. Case in point is the acquisition of RJAF platforms.
A good mix of Air Superiority fighters in the shape of F-16's upgraded with BVR capability -- enhanced capability JFT for point defense and interdiction role up from those currently available PAF in the shape of F-7's and ageing Mirages is a very good mix.
This is a can do thing for PAF keeping in view the various constraints being faced by PAF and Pakistan as whole.
Therefore, in future i see more purchase of New build and second hand F-16's and constant upgrade and SLEP program for those machines.
Any infusion of SU Machines either the SU-35 or the lesser Chinese equivalent would be an added bonus for deep strike/interdiction.
However, IMHO -- availability of an up-rated engine for the JFT is turning out to be the biggest challenge for the overall program.