fair enough, But as a resident of North East, I'll point out the difference between your opinion and mine. You're free to disagree if you like.
It is certainly true that all nations that go to war estimate and expect casualties. It's already factored into their battle plans and logistics plans. However, you can only predict such data to a degree of accuracy, and that too if the progress of the war is in line with your plans.
You can look up any war, any battle, any campaign from any period. The greater the delay/holdup, the greater the deviation from expected casualties and losses. This is partly the reason why superior equipped/trained armies aim at a rapid penetration/pincer/thrust campaigns, instead of slower general advances.
And in that respect, the terrain and topography of NE India is a quagmire, both metamorphic, and literal. The first echelon of the IA defenses stretches over the very difficult Himalayas. And unlike what many here might imagine, mountain warfare will focus on key passes and passages that allow logistics supply to the divisions of fighting troops. And as with any fight in confined space, the attacker loses the advantage of superior numbers.
Assuming PLA breaches the first echelon, they will come up against the second echelon, stretched along the vast flood plain of Brahmaputra.
The primary problem for the advancing PLA is that they will be an infantry heavy force will no armored support India on the other hand, has around 6 regiments of tanks (T-72) in NE, with an additional 6 regiments of T-90MS expected. Combined these come to around 2 armored divisions should the army command decide to commit them as a cluster. ( Over and above that, excellent rail networks should enable India to deploy entire divisions of armor on short notice.)
And need I remind you that infantry in plains without armored support tend to get slaughtered, bravery notwithstanding?
The next problem is that India controls the various flood gates to the Brahmaputra and its tributaries. In case of a breach in the defensive line, India will simply flood the area, an area denial/ scorched earth policy if you will. (There is a precedent for this. In 1965, India did indeed plan to release all the water in the dams in Kashmir to flood Pakistani Punjab plains, in case Pakistan breached Indian defenses around Achnoor.)
There are more problems, but am not in the mood to state them right now.