You have to remember one key thing, there are 2 world titles, 2 brands, and because of a larger audience, the internet, and more, world title reigns are much shorter, in an effort not to seem stale.
That being said, I don't really think it was Miz's time, I just can't see how credible this reign is going to be. Miz has no credibilly not just because he hasn't beaten a legit opponent in god knows how long, it's because the Miz isn't strong enough in the ring to be considered a thread.
I mean look at Miz, he has no in ring style. He's not a power guy obviously, but he doesn't have any speed, he isn't a high flyer, isn't a technician, submission artist, or anything, he does a couple of generic moves which he often doesn't really do well, and then an awful finisher. Truthfully I can't ever really see him beating midcarders, not too sure how WWE is going to sell him beating legit main. It's ok to be a chicken shit heel, but there has to be some kind validity to make it an interesting matchup. Of all the other top flight heels, Sheamus, Kane, Punk, Jericho, Barett.. I can see all of them actually winning against any of the faces legit.