Now there's a limit to the reduction you can do on a single engine 4th gen. fighter... now is that worth the cost involved in such modification.... even the slightest of changes would require the entire process cycled again right from the design to windtunnel testing to test flight in PT stages FBW laws rewritten.. etc..etc.. more money spent and more importantly time spent and resources allocated...Leave aside US(they have a lot of resources and their Companies are aviation giants)... even Europeans and Russian can't afford it... and in the end of all that what you get is a quasi-stealth JF-17 which an ESA Radar on Mig29 can see from 90km and track it from 80km... what advantage does it provide here ?.. (take into account the AWACS and lot bigger ESA radars on planes like Su30 which would see it at 100+ km and track it from such distances aswell).... now taking the time you spent for making it quasi-stealth into copnsideration and keeping the budget of PAF in mind most of the resources would be allocated towards the project as it has been in past... and after 5 years when you come up with JF-17Stealth block II the neighboring AF would be inducting 1st squadron of their 5th Gen. plane... hence money, time, resources all wasted gone in drain.
Now considering another path and leaving what the JF-17's body structure unchanged and investing in strength multiplier stuff like ESA radar, IRST, Good ECM package, next gen weaponry like ramjet ALRAAMs more powerful and better engine... which would make it more competent against the existing 4th and 4.5th gen. fleet in the neighbourhood at least.