That is a brilliant post and I concur. It is what all contemporary naval wars from WWII to now has taught us - submarines and aircraft are the key. For some odd reason it missed the PN.
The only thing I would add are:
1. Unmanned UUVs (robotic mini submarines). Basically you can't control them much, they are like mad and suicidal attack dogs. You set them loose, give them an area to go to and create a mess. Say, for instance, one putters off from Karachi, no control, but goes underwater, heads near a designated Indian port, if something shows up from an East to North West vector, it gets a bad day.
If nothing shows up, it reaches near the Indian port, lays mines, and shoots torpedoes at any and all boats at the port. Once it is out of ammo, it blows up taking whatever else it can with it.
Imagine the headache that would create for every single Indian port and sea lane on their West coast. It would be a nightmare to face. And at the cost of no Pakistani lives and a small investment.
2. A 400 - 500 ton mine laying submarine. These were in fact the subs that got the most kills during the War but were the cheapest and smaller submarines. They don't need great loiter time or deep diving capability. This is how the Germans used them - they go off a port, stay abou 50 meters below the surface.
Reach near a port / sea lane (perhaps at a safe distance from the mad dogs we sent earlier in (1). Lays mines and comes back home. No need for deep diving stalking or staying on station to get a hot kill.
As the mad dogs start doing their work, the mine laying submarine turns around and scoots back home. I'd simply add one more addition other than the German concept - a single ballistic / cruise missile at the back to fire off as the submarine leaves the operational area. Aimed at the general direction of the Indian port, the cruise missile / ballistic missile will lock on to any boat it sees or simply crash into the port.
This would cause the Indians to get upset and set off a knee jerk reaction, speeding up in their frigates and destroyers, exactly to the mine field layed by the mine layer and the UUV. By then the mine laying submarine has already left the area and the IN warships are headed straight to their designated mines...
How much would these UUVs and submarines cost? A fraction of the cost of all these big ships and big egos. But the damage they would do would be disproportional. As was in fact the case both in WWI, WWII and the Falklands.
I once met a US senior officer who told me a story about their submarines finding a gigantic fleet of British warships at the bottom of the Atlantic, between Argentina and the Falklands. He laughed and said that the British were too ashamed to admit how much they lost and hid their actual losses by a gigantic margin.
@MastanKhan thought you may find that interesting.