They are yet to completely wean themselves off of liquid fuel missiles.
Not only that, even the solid fuel ones like Shaheen and Ababeel still rely on control fins for maneuvering the missile body. Points toward a flight-control system that is not even as advanced as what India had way back in 2006 with Agni-3.
Five years on, we eliminated vented interstages with the Agni-4 in 2010-11, further improving aerodynamics.
Both advancements culminating in the Agni-5, one more year on in 2012.
I don't think even the latest Pakistani ballistic missiles (like Ababeel, first test 2017) have progressed to a technological level that can be said to be significantly better than our Agni-1 (1989) and Agni-2 (1999) in terms of critical enabling techs like flight-control, metallurgy, propulsion & electronics. That's despite getting huge help from China/North Korea.
And our latest standard of BM tech, A5, was tested first almost 7 years ago. Imagine the improvements in meantime.
India truly provides quality R&D and funding for the Ballistic Missile arsenal and we can easily see major tech breakthroughs from time to time. And that's only on the surface - what we can see and analyse on the open domain. Underneath that, each developmental test launch probably brings untold amount of new tech and improvements we don't get to know about.
Coming to MIRV, it's clear to see that what the Pakistanis are trying to do hear is sort of a 'poor man's MIRV' kind of contraption. Understandable considering their ballistic missile technology itself lags India by about 20-25 years. Which casts doubt on their ability to deliver a proper, reliable MIRV solution. For all we know, it could just be a unitary warhead in there.
Our MIRV plans are obviously a lot more far-reaching and we cannot afford to get caught up in ad-hoc solutions. Our focus is in a system-of-systems sort of approach, the kind of strategic deterrence we require in the future is to be delivered in a very well-thought-out and long-term perspective plan:
- Truly World-Class ICBM: One might be forgiven for thinking all BMs are same but it's not so. Types like Trident-II D5 and French M51 are so far ahead in terms of technology compared to anything in the Subcontinent it's unbelievable. And make no mistake, any country that knows how to put 2 and 2 together can make a missile. But making a very good one is for a select few. And it cannot come from any country that does not have a very well established and functioning space industry - because this is, after all, rocket science. India will possess a truly world-class ICBM only in the form of the Agni-6 and its SLBM cousin the K6. We may be 25 years ahead of Pakistan, but at present our ballistic missile tech (straight from basics like burn efficiency) does not compare favourabley to leading Western BMs. That will change with this new gen of BMs in the next decade.
- Reliable, Constant & Truly Survivable Deterrence: Just like with the MIRVs, we cannot afford to get caught up with ad-hoc solutions for deterrence, like Pakistan's planned SSB fleet (which any SSN can hunt down and destroy with impunity). Our plans need to (and do) lie in possessing a truly survivable deterrence platform - such as an above 12,000-ton SSBN with minimum 12 launch tubes per boat. Nuclear-powered subs can make mincemeat of diesels in the long game, the reverse, not possible. If an Indian N-sub does not want to be caught, there's nothing a Pakistani diesel sub can do about it. But if a Pakistani diesel/AIP boat wants to stay hidden, it doesn't really work out in the end. The N-sub technology we've been investing huge amounts in since the 90s will pay off in the 2020s and 2030s when the S-5 and Attack subs start showing up. The sub game (both attack & deterrence) will be fully in India's favour. And with that, comes a truly constant & survivable deterrence.
- Scalable, Advanced MIRV Buses: The Indian BM program will see 4, 6 and in future probably 10-MIRV bus designs as standard (lot of commonality between land-based and sub-based BMs will be there). The aim is to ensure a credible deterrence value against China, which by extension means an overwhelming capability against smaller threats like Pakistan. One mustn't forget that all this stuff - Advanced BMs, MIRVs and SSBNs, is being worked with China in mind. We don't need all this to counter Pakistan - for that existing Agni-1/2 and K4 are more than enough.
- Ballistic Missile Defence: When all is said and done, no one can deny that India is the only player in the Subcontinent that plans to be in a potential nuclear war, and get back up again. For the Pakistanis, the only thing they can control is when to press the button. After that, the nation of Pakistan will most likely be completely destroyed for all intents & purposes, owing to a complete lack of theatre-level BMD, and no plans to acquire one either. A one-throw-of-the-die nuclear policy if ever there was one. One of a kin with North Korea. The scary part is, very few people in Pakistan actually realize this.