i think anything short of the total subjugation and pacification of india would be bad for china/pakistan because a wounded india would only drive itself further towards the western sphere of influence.
wounded India going to western influence isn't a major concern. because fundamentally, India is large enough to be a great power. So India would never become a full subject to the west, India's alliance to the west will only go as far as their own survival.
however, a wounded India would mean more border revolt and unrest. India have more ethnics than China, and wounded India means less central control over those minorities and they would want independence. Those minorities would have some population on china's border, and China would have to get involve in counter insurgency, which means, very expensive.
For example, nepal and bhuthan are more pro china due to India directly absorbing sikkim. if india is weak, then they would worry about china absorbing them. plus India would lose central command on many ethnic minority region, and sparking more war of independence and nationalism. the largest ethnic in india is only 200 million. their populations is 1.4 billion. so there are so much internal competition and rivalry in india.
I think a long and more escalated war would not be clearly favors india. because india is also heavily dependent on foreign import for arms. india would have more credit to import more arms. but pakistan can still import extremely cheap and cost effective drones. the ethnic composition of india would make it hard for them to use nationalism to win this war.
Russia is majority ethnic white slav russian. India isn't majority one ethnic. while pakistan have less ethnic diversity than india; on defence, most of the ethnic would unite to defend pakistan, because their own survial depends on it.