The only surprise was that Melisandre survived. After the age thing last week, I thought she’d do a Lord Beric and die after giving Jon the kiss of life. If she’s 400 years old, and looks every day of it, it’ll be hard to turn her back into a sex symbol. That would be creepy even for HBO. At that point, she loses much of her utility for HBO storylines, unless GRRM has yet another big contribution in mind before she’s done.
In the books red priests can continue to bring people back to life. In fact this is an entire story line the show hasn’t touched on. John Snow will probably being dying quite often. They will need the red lady around to revive him.