Yeah, and now think of a weak Pakistan in the hands of Mullah XYZ. Compare that with the current situation in the valley.
Just for the sake of argument - I disagree.
The thinking in the more extreme sections of the Indian establishment (going by certain civil and military commentators) is that it is the Pakistanis establishment that has "brainwashed" Pakistanis into "hating India" as a raison de`etre, and the focus on the Kashmir issue is merely a vehicle for that hate and a means to perpetuate it.
This section of the establishment does not really believe that Pakistan will ever be satisfied with Kashmir, and that the "Pakistani establishment" will find some other means of perpetuating hostility with India if Kashmir was resolved.
If this is the view held by Indian decision makers that are a product of the above thinking (and I am not suggesting it is), then the bigger threat is not a Pakistan that disintegrates, but a strong Pakistan that continues to hold to a vision of "hatred towards India" as a reason for existence.
In their view, a united Pakistan, composed of diverse cultures and ethnicities, with tensions between these ethnicities simmering under the surface, needs that hate towards India to survive as a united entity. A disintegrated Pakistan would split along those ethnic and cultural lines and therefore the need for propagating a "hate for India" would no longer be necessary.
This view has become even stronger over the past few years as India has leap frogged over Pakistan in almost every sector, and the prosperity of the present is providing an additional, flawed retrospective justification for the argument of "hate India".
I am basing these observation on articles and comments by Indians that I have read over the years - by no means am I suggesting that this is the prevalent view in India, or that it is the view that prevails in the corridors of power, but that it exists.