I really think the IA should stop raising religion/caste based battalions altogether. As the article states, it was started by the British based on their "martial race" theory.
The point the IA is making that units gel together if they are from the same background is understandable. But for that they don't need to belong to the same religion or caste - they just have to be from the same region. So while the IA should continue raising Punjab regiment and Madras regiment and Jammu Kashmir regiment, it should progressively end raising all-Sikh units or all-muslim batallions or all-Jat regiments. In Indian society also, in schools, colleges, tea shops, people gel together if they are from the same region - and not based on the same religion or caste.
So not only should they reject calls for new caste/religion based regiments, but they should start decommissioning regiments and battalion that are based on race or religion or caste. Sikh regiments, Rajput regiment, muslim battalions within certain regiments, should all go away. Make the raising of units purely on the basis of region, to form regimental unity and camaraderie. Operational units on the field should be all India units, composed of battalions from every region (which is already the case).