A rotary wing AWACs system is fine for STOBAR carriers like the Vikramditya and IAC-1 where the IN has purchased KA-31s AEWs systems but for ACCs like IAC-2 that will be larger (65,000+ tons) and that will most likely be CATOBAR configured the fixed0wing AWACS systems like the E-2D is the best option as they can fly higher,further, faster and with a more powerful and capable radar system. The E-2D is the most likely candidate for the IAC-2 sir. The increased cost is no real issue for the IN especially when this system will be procured in a few years when the Indian defence budget will be significantly more than it is today and the addtional cost is more than outweighed by the addtional capability of a E-2D like system.
The reason the UK and Russians use roatary wing assets is because of relatively lower cost and the small(ish) carriers the AEW systems will operate from.
Then why not simply purchase a platform that may house the systems of the DRDO AEWCS?
After all, the E-2 comes with another electronics logistical headache.
If it is possible to find a platform that can be made carrier capable(I am confident that the Russians have such a platform sitting somewhere) then it would be more beneficial for the IAF/IN co-operation and for the Indian defense industry.
Moreover, less training and logistics strain at any point even with the optimistic budget figures means money is available for further upgrades to IAC 2 and/or other assets.