Daleks Again!
When asked if he felt compelled to bring the pepper-pots back, Moffat explained, “You don’t have to bring them back. There’s absolutely no law that says you have to bring back the Daleks. But occasionally, back in the day, when I still looked at the fan stuff on the internet, there’d be people saying, ‘Oh, the Daleks are back every year!’ But for kids that’s ages to wait for a Dalek story. You have to think of the Daleks as almost a regular character.”
He continued, “They’re one of the regulars. But they’re brilliant. They’re still the number one Doctor Who monster. They were invented in 1963 and they’re still number one. That says there’s something very magical about them. We haven’t managed to top them. So of course you’re going to bring them back. You can pretend you’re being a grown-up and say, ‘Oh, it’s the Daleks again!’, but secretly your little heart is beating, because it’s the Daleks.”
He also teases that the other returning monsters, the Weeping Angels, may be a little different than last time, “They have more powers than you thought. And you are not safe just because you can keep your eyes open!”