Based on the information I've been exposed to by attending numerous Indian foreign policy discussions and symposiums held by government officials (civilian and military) and academicians alike; I think your hypothesis regarding the current environment is incorrect.
The trend if anything is rapidly reversing. Even for the most ardent Indian conservative, currently the biggest supposed anti-Indian vector in Pakistan is radical Islam, not a nationalized social movement promoting hatred towards India. The former has the ability to seed through virtually every section of the society regardless of ethnic or cultural differences and is for the most part independent of the latter. As long as India maintains military, economic and diplomatic superiority over Pakistan it is a lot more convenient to have Pakistan as monolith that can be vilified and tackled easily. What they find dangerous and most of all frustrating is that Pakistan is anything but a monolith (IMO it was dumb to assume this in the first place). To have a Pakistan that disintegrates, but with the various factions still holding on to radical Islamism is the worst possible scenario because that would mean multiple fronts where nobody can really be held responsible or vilified decisively.
From the centralist -> liberal spectrum's perspective, Afghanistan and now Iraq serve as solid examples of the disastrous consequences associated with sharing a contiguous border with a fragmented failed state. Such a situation for India would pretty much ensure a complete economical collapse.
Hence given the unlikelihood of Pakistan superseding India economically, militarily or diplomatically in the foreseeable future, any threat posed by a unified Pakistan pales in front the fatal risk associated with a fragmented Pakistan.
This is all very interesting- but I was wondering if you ever heard of the term divide and rule? Well for starters it always works...provided you are able to divide them that is.
Frankly Pakistan has never had military superiority over India, but still we are India's arch rivals aren't we? The greatest national security concern they have. That's been the case long before Zia-ul-Haq or Islamization or Talibanization. Indias military superiority over us wont get suddenly reversed if Pakistan breaks up and extreme elements get a bit of it; in fact quite the opposite.
Point is this "we are against Talibanization not Pakistan" thing is just a blanket cover for their anti-Pakistani ambitions cleverly designed to help them gain sympathy from people and places that matter. You would have noted that Indians are always the people foremost in demonizing Pakistan as the worlds biggest corruption-dictatorship-military-Islamic-terrorism-irresponsible nexus. In fact they go out of their way to do so.
So back to the point, the Indians hate us. United we are still a great threat to them; today its Islamic terrorism, tomorrow it will be something else but their feelings towards Pakistan will never change. They will just come up with new fancy ideas and ways of demonizing Pakistan in their 'policy discussions and symposiums' and make themselves out as innocent and responsible heroes who are trying to save us from our own daemons. That's why you might have noticed the contradiction in their own line of thought Agnostic Muslim was talking about. So when the world has forgotten about Islamic fundamentalism there will be something else Pakistan has done wrong that India will feel the need to remind the world about...
India many have military superiority towards Pakistan, but lets be honest, they would love to get more. What better way to break Pakistan's resolve? Of defeating or at least seriously weakening Pakistans military? Depleting its resources so it doesn't even consider a confrontation with great and mighty India?
Militarily the idea that India wants a united Pakistan with a professional, well equipped, trained, resourced and respected army with nothing to do but sit around all day and practise like hell for open war against their nemesis is simply pathetic. Of course they would love for us to batter our teeth blunt against our own people. I don't mean to say the Indians are evil or vile or anything(at least not because of this) but this is just something any reasonable foe would do or prefer.
Ofcourse, this is just my view, and there is merit in your view too.
support of holding on to Siachen given its critical strategic position
I frankly have no idea what you are taking about dude. The whole Siachen affair was pointless and pathetic from the start, there is no potential for India to achieve anything in Siachen, other than perhaps loose 4 men a week. Everyones said it, Indians cant come down and Pakistanis cant go up. The situation is a complete pointless stalemate. It would be best if both sides stop suffering, but since India started this and there is a factor of pride involved it is easy to see why no agreement can be reached. Also there is the fact that if India pulls back they will never be able to retake what they have again...so the IA stays and the issue lingers on and brave men die.
Again thats your view I suppose, and this is not the place to argue about it. I can see and appreciate your Indian military-line of thinking though.