This shows you're a layman who has no idea about how a military operates and what is the concept of COIN or what is low intensity conflict or any thing about the presently prevelent assymetric threat environment. I will answer your querry in parts.
1) Military units are rotated after certain time , not kept at a single place throughout their lives, it is stupidity to even assume that. They are rotated not only to LOC but other parts throughout the country and viceversa. This is common in every military including yours.
2) If troops are inexperienced why do Jordanians, Saudis, Iraqis, Nigerians and Srilankans send their troops to be trained at our Counter Terrorism Training centers. Or why do Americans, Russians or the Chinese train with us. The concept is to share the experience of real time warfare , since these countries experience similar situations i.e asymmetric threats.
3) Now lets see if Zarb-e-Azb qualifies which according to you it doesn't. Right across the border in Afghanistan , 28 country coalition of one of the world's most powerful militaries have failed to counter the growing insurgency since last 17 years. If assymetric warfare wasn't considered a serious threat in today's environment then Americans would have won in Afghanistan, there would have been no IS in Iraq or Syria and Russians and Americans wouldn't have been fighting in Middle East. These wars have costed thousands of lives for militaries of great powers and are the biggest challenge for today's world. Pakistan has defeated and pushed Uzbeks (IMU), TTP (part of which merged into IS in Afghanistan) across the border, thereby ensuring a full throttled Control, Hold and Build strategy. It is the only country in the region perhaps other than Srilanka to have successfully defeated an insurgency. Your view of today's threat environment is absolutely naive. As a student of International relations I can tell you, had you been one, the way you dismissed the importance and experience of Post-Modern warfare, you would fail in the most basic test.
4) Human life no matter of which country is important. As I said again, in statecraft and the games nations play with each other , militaries and soliders are used as instruments of power projection. It is realpolitik which governs the relations, morality takes a back seat , these are different from induvidual one on one relations. While my sympathies are with families of those who lost their lives, national interests tend to be supreme. For that Pakistan resorts to reciprocity principle and that is what we are seeing at LOC.