The sweet spot for current generation BVR missile (before Meteor) effectiveness is around the 60 kms area. Beyond that, the Ph/Pk drops drastically and any hit is unlikely to be anything but a fluke, especially against a competent opponent.
BVRAAMs are rarely if ever fired at their maximum ranges. Usually, either ROE prevents this, or the pilot's decision to wait till targets are closer in order to ensure maximum probability of kill.
AEW planes & tankers ofcourse cannot maneuver as well as fighters can and will be susceptible to a higher chance of hit/kill.
In the Indian context, the best way of ensuring an Anti-AEW capability is to employ high-speed SAM rounds such as those we're getting in the S400 package. As far as air-to-air option goes, the Meteor affords the best chances of taking out lumbering targets at extremely long ranges. Do note that MBDA and the countries involved remain highly guarded regarding the effective range of the Meteor missile. The quoted "100+km" figure is nothing but the very bottom end of the max range.
A range of easily twice that of the C-7 AMRAAM is likely.
The lack of strategic depth on the pakistani side combined with S400/Meteor usage ensures it will be extremely problematic for the enemy to successfully operate AEW aircraft beyond the very opening stage of an all-out conflict.