It CAN be cumbersome, but as I mentioned in an earlier post, the guys selling sim cards at Kochi airport had the process down to a T: not more than a minute or two for the paperwork and a couple of hours for activation. With luck you'll have the same experience at Bangalore airport.
You must know that in India you take what's available and make the best of it. And if nothing's available so be it.
Very practical and pragmatic advice for short term infrequent visitor.
Unfortunately, that is also the attitude adopted by most locals (even educated ones with plenty of resources of time, money and connections)
Result is that, there is not much demand for efficiency, common-sense and optimization- leaving India as India.
("We are like that only" is stated shamelessly as if it is sort of badge of honor.