Realistically speaking will we get theatre commands ?
US has divided entire world into theatres, which are huge in size. China has done the same within the country. But India has a third the land of China, and theatres will be much smaller. Army and Navy have major roles to play and will definitely have theatres where their heads will lead. Air Chief Marshal wont be as lucky, just like in US theatre command Chief of Air Staff is not a combatant commander, but generals and admirals are.
It's no surprise that Air Force opposes it. They dont want to lose autonomy. Despite the differences I feel they should accept theatre command, they will omnipresent in any theatre.
South Indians were historically more orientated towards the sea due to the lack of a land border and the constant shitfighting happening in North India. It's actually part of our culture to be more seaworthy and support the navy and merchants.
Since South India doesn't have any use for land based military, and since North India is predominantly preoccupied with land based wars, why not make South India the home of India's navy?
The entire military force of South India could be replaced by the navy, while North India retains its army and air force; South India would be responsible for providing naval forces for the North, while North India will be responsible for providing armed forced for the South.
A gendamerie would be responsible for riot policing, VIP security, counter-terrorism operations, policing in militant areas, coastguard, search and rescue, overseas peacekeeping, and special operations.
A navy would take control of all other military duties. I would suggest that India has around two or three supercarriers to be able to project its armed forces to distant lands around the globe, while its numerous destroyers/frigates should be able to accommodate three aircraft.
This would make the military in Southern India, which only really has naval wars to fight, far more efficient at fighting its external threats. It could literally become the coastguard and naval headquarters for India, as tradition would say considering South India was always more orientated towards the sea.
I think its important that India has strong anti-submarine equipment (I suggest aircraft carrier based ASW helicopters) and a few destroyers/frigates equipped with aircraft that can fight in the South China Sea and Arabian Sea.
The majority of India's wars appear to be on its northern front, against the Middle East primarily, but also a moderate threat from China.
I also think it would be progressive if India entered into a strong military alliance with Sri Lanka in order to counter the threat from China and Islamists; we can cooperate on naval affairs and reduce Sri Lanka's military debt.