Ok, here's some analysis for you.

Contrary to my expectations, fares are actually lower ex-JFK (maybe there's a sale on now or something)

ex-BOM (WREYOI): 1486 1685 2018 2462 3429 2950
ex-JFK (WREYOI): 1151 1308 1466 4355 ----- 4836

The Y fares ex-BOM have a INR2k change. O fare has INR3k and I fare has free changes.
All the fares (I didn't compare J/C) have $400 change fee. And they require a min stay of SUN for Y fares and 7 days for J fares.

Clearly if you're likely to make changes, paying $400 each time is not the way to go. The fares ex-BOM also have no minimum stay. This would actually be a great strategy for someone based in the US - cheap changes ex-India and no minimum stay. Though if your dates are fixed for any trip (say its last minute departure from JFK and cheap fares are available and you know when you're going back) then you're better off saving $300-400 on the WRE fares from the USA.