Watching the election most of the night it was extremely clear that when the pundits thought that the election was going to be very close, it was believed that there would be big noises about PR and that a coalition was a certainty and so a compromise had to be made.
As the evening wore on and the sheer scale of the SNP wipeout became clear, followed by the collapse of the Labour and UKIP challenge to the Tories in England, the noises about PR slowly vanished.
I'm pretty sure that it is buried for the next 5 years now. After all, why would the Tories try and change something which gave them a majority government? Under PR they would not have won.