What does this have to do with hunters being a great at 1v1 encounters again? Hunters have always excelled at 1v1s, even since classic. Good pet control, refusing to let any melee class near you outside of your own mobility cooldowns, and demolishing any cloth class, hunters are powerhouses in solo encounters.
As said before, any hunter smart enough to keep his distance and keep his pet passive outside of cooldowns won't lose. Even if you're being defensive with your runic power, you're not going to generate a lot when you're constantly chasing after a hunter. Death's Advance is a nice cooldown, but you'll just end up getting scattered when you use it, and then possibly eat a freezing trap after that. Any time you grip, you end up eating Narrow Escape's root from disengage (and your 4 piece is nullified by a silencing shot).
Of course any poorly played hunter will lose when he panics and pops every defensive cd h has at the same time, but a good hunter will toy with you.