I think India doesn't give a damn about Kulbushan. It only wants to create an impression enough was done for his release. Morale is important part of intel agencies, the worst fear is being left to rot behind enemy lines abd forsaken by your Gov. How much they might say spies are ready and trained to be dispensible, it is never the case. Indian Gov would rather create drama from the retired Colonel capture Saga as a rebuttal to KY and have no more interest in swap before it. The hanging might cause a bit of hurry in Indian ranks to create an impression of a rescue for KY which might result in mistakes, but more or less both men's fate has been sealed unfortunately.