Hon Sir
I would respectfully disagree with you. Pakistan achieved the gun type nuke long back in the 80's during Zia ul Haq's era. Mirage aircraft were modified and to carry out an operation. Pakistan has reached this stage where it has a very modern missile program. Do you honestly believe that Pakistan would spend all these billions and bear the brunt of international community to just achieve a gun type solution. That itself would be unacceptable to the strategic high command and the DG would be fired from his job outright. Pakistan has been conducting cold tests since the end of late 1990's and the introduction of super computers have made the process even easier. Lack of nuke would have ensured a military strike from India post the 26/11 attacks. I can assure you that PA Generals are confident of mating a strategic nuke and delivering it to India. Under the leadership of Lt Gen Gillani whom i might add is a very fine officer, the assembling time has been brought down considerably. Thus, i would conclude by stating that please don't make the mistake of thinking that Pakistan does not has the capability to miniaturize her warheads.
Though I am no authority on the subject being debated here, whatever open source material available suggest, no one (outside the subcontinent) is confident that Pakistan and possibly India too, have till date, been able to miniaturize their warheads, enough to mate them to missiles.
Hell, people even doubt Israel's capabilities in this regard. The most notable reason being stated is the lack of further tests that is required to validate the designs. Let me evaluate a little.
Even though the five nuclear tests carried out in the Ras Koh Hills were widely publicized, claiming that the tests involved one large and four "low yield" tests, something that most western experts disagree with, specially regarding the yield. Further, there are many diverging, even contradictory views expressed by the very people involved. Samar Mubarakmand, who was in charge of the Pakistani Atomic Energy Commission's Directorate of Technical Development, claimed that the test tunnel, rather than being straight, was "designed in the form of a double-S shape".
Pakistani Defence Journal's claim that the tunnel had a "fishhook" at the end to allow for a device emplacement that would result in the tunnel self sealing after the detonation.
Another report also claimed that the tunnel was "M" shaped, suggesting that the tunnel may have also bifurcated near the end to allow for the single large test to be emplaced in one fishhook, with the set of four smaller ones possibly at a second fishhook.
It thus seems absurd that a ultra serious thing such as a nuclear test, which involves detailed, layered, well documented and elaborate planning is marred by multiple contradictory claims.
Also, plutonium weapons are lighter, and have a higher explosive yield than weapons based on enriched uranium, which have been the mainstay of Pakistan's nuclear weapons programme since its inception in the 1970s. Recognizing that Pakistan requires lighter plutonium warheads for miniaturization and fitment on missiles, the development of plutonium reactors and reprocessing plants needs greater momentum. Pakistan's efforts to build plutonium weapons capabilities started quite late, i.e. in the 1990s. Pakistan today has one operational plutonium reactor in Khushab, whose capacity is estimated to be between 40-50 MW which doesn't seems adequate.
All the nuclear haves, had their fair share of duds and test failures, before they could actually fit a working warhead into a missile. In the process which involved multiple tests, they have collected enough data that can be consumed by super computers in order to simulate a real test, something that Pakistan nor India can't boast about. If you thus look into the very fact, that both India and Pakistan have so far kept their nukes in component form and have not actually mated the warheads with the delivery platform, it gets obvious that their respective programs are still evolving and there's a lot that still remains un-fulfilled.
For any foreign power, which might seek to takeout Pakistan's nukes, a 3:1:3 hit in all the three elements of its nuclear forces, namely the warhead, the delivery vehicle and the C2I nodes, will be required to say the least. As it seems, Pakistan has done its math and has decided to make this job extremely difficult, if not impossible, by going for maximum number of warheads that it can get. Once achieved, it will give your nuclear forces the required confidence to retain the capability to nuke one or more targets, whether counter force or counter value, even in the worst possible scenario. India's case in that respect is different, as it seeks to just maintain the balance vis-a-vis China and Pakistan by going through the triad analogy.