The first thing you notice is the dragon’s size. The creature no longer looks like an exotic bird that Daenerys Targaryen (Emila Clarke) can put on her shoulder. It’s now like a medium-sized dog. Only if you were to put this thing on a leash and walk it around a park, other pet owners would run screaming (you only get a slight sense of its increased fearsomeness in the current trailer, which shows a dragon flying from behind).
Over on the Thrones set, showrunners David Benioff and Dan Weiss sit at wooden table that’s lavishly adorned for King Joffrey’s dinner feast. They compare the dragons’ growth to the way a baby crocodile or rottweiler can start off cute, then turn into a monster. “This is an interesting time for the dragons,” Benioff says. “When they were born they were adorable. Last season, as you say, they were still kind of cute. But now they’re turning into proper flying dragons. One of the interesting things about the books, and hopefully the show, is that the weapons of mass destruction in this world are living breathing things. And as they get older that presents problems.”
“They’re still cute to Daenerys,” Weiss adds. “They’re her babies. But her babies can burn down a house in a few minutes and they’re getting increasingly terrifying to everyone around her. At some point she will have to reckon with the fact her babies are all grown up.”
And one with George R.R. Martin talking about adapting the series for tv (among other things):
RAR: There do seem to be an increasing number of deviations from the books — not so many in Season 1 but more in Season 2…
GRRM: I think that’s a process that’s likely to continue, and some of that is just the nature of the process. I mean, when you make… Everything is related to everything else. So, if you make a small change in Season 1, it could lead to a really big change in Season 4 because the thing that was supposed to happen didn’t happen and the guy who was supposed to come in never appeared and it was just a line in that book but now you’re in this later season and you don’t have him set up. So, everything gets magnified and you have to deal with it.