It has always been all over the place. Sometimes someone gets a blaster shot and dies immediately, other times they don't. A starfighter gets hit multiple times from capital ship turbolasers and keeps on trucking. A single shot from a snubfight to a cruiser's bridge and we get Mary Poppins. It's always been whatever is most convenient from the story standpoint.
Marry Poppins Leia is the poster child example of "plot armor."