What feedback did you receive from the last expansion, Cataclysm, and how did that help shape this expansion?
DW: "I think some of the feedback was that the dungeons were fairly hard, because the content was fairly hard. A lot of people loved that, right? Hardcore people loved the challenging hard content. This time around we have Challenge Modes for all the dungeons, which is specially for a timed, really difficulty-tuned run of a dungeon for hardcore people, to get these bragging rights.
"Post the best time on the leaderboards, get the best armour, and really prove that they're great at their class. But then, the base dungeons are tuned to be a little less difficult, therefore they're something people can do in half an hour, to get in and do their daily dungeon.
"Along with that we have a bunch of brand new features to appeal to all sorts of different players. There's the pet battle system for collectors in the game, we have new factions for people who are interested in the story, or collecting mounts and lore. Really, to just put in features for all sorts of players. We know our player base is very passionate and is made of all sorts of gamers."
SM: "I think one of the biggest takeaways was we wanted more things for players to do when you hit the maximum level with this expansion, which is why we've provided so much more different types of content than we did before.
"Previously our expansions have always had super strong dungeons and raids, they provided some wonderful questing experiences as you were going through, but with Cataclysm I don't think we had enough stuff if you didn't do raids.
"And certainly we've improved that with 'Looking for Raid' recently, so you don't have to have a guild to go in. But still, there's this feeling that we wanted to give players more things to do.
"For a lot of players, Warcraft is so cool that they want to spend a lot of time here, and we just needed to provide them with different things to do, and that's what you'll see in Mists of Pandaria, it's just all the different types of content, some that's not traditional for Warcraft but are still really cool, like the Pet Battles."
Mists of Pandaria seems much lighter in tone than Cataclysm. Was that done on purpose?
SM: "Absolutely. After Wrath of the Lich King, where there's a threat to destroy the world, and another expansion like Cataclysm where Deathwing did wreck the world, after so much 'We have to save the world, we have to save the world!' it's like, hey, let's go into an expansion where it's really about exploration and mystery, which was a word that popped up in a lot of design things.
"That sense of going into an unknown land, this place that just rose out of the mists and no-one has ever seen it before and it's all different out there, so absolutely - that was a huge goal."
The Pet Battles have been compared to Pokémon - would you say that's a fair comparison?
DW: "We love collecting-style gameplay, we have influences from all sorts of games. Collecting is something that has always been part of World of Warcraft, especially your companion pets. So many have hundreds of companion pets, collecting the cats to the rare things that have resulted from the various factions, now they have more that they can do with it.
"Not only do they level those pets up for battling other players, they can go into the wild where we've populated all these new pets, like squirrels and different creatures like water elementals in all different places, and tame those, capture them and level them up, so the collection can get huge.
"It's another example of content for players that maybe don't have that much time, or are more interested in the collection gameplay. They can build their collection, log in, have some quick little experiences; this new tactical, RPG mini-game is a really fun way of doing that."
Was the Challenge Mode a direct result of Cataclysm or is that something you wanted to introduce for a while?
SM: "I'm pretty sure we wanted to do something like that for a while. The idea of a piece of content where, we've had PvP (player versus player) before but this is a type of content where you're in a dungeon, like you normally do, but there's a competitive element to it because you're trying to get the best time. That's something we've thought about for a while, and we decided that this is the expansion where we really start in that particular direction.
"[With] normal dungeons and raids, it's about you doing that content, you get items and you improve that character. With Challenge Mode, it's about the skill involved. We actually lock the power of your item levels so it's a constant amount.
"The way you improve your times isn't just to get better items like you usually would, it's really up to players to play more skilfully. That's something that I think adds a whole lot to Warcraft that we haven't seen before, the purely skill-based player versus environment content."
DW: "And the rewards you do get, the armour, doesn't have stats on it. It's purely used for transmogrifying, where you can turn your existing armour to look like this armour, so you make yourself look very unique with this armour you can only get from getting a gold medal, for instance, from Challenge Mode, and people know that this guy is the best of the best."
Did this mode require a new approach to balancing and testing? Because I imagine there's nothing quite like this, where you have to get the fastest time possible.
SM: "Certainly, compared to normal dungeons, the creatures inside hit harder and there's modifications to the way they're placed to provide a little more challenge as you're working your way through. When we do normal dungeon testing we use a very broad audience because we want everyone to get through this dungeon and have a really good time.
"With Challenge Mode, within the office we found the best players we could find, and did internal tests and they would literally spend multiple days just going through each Challenge Mode, and seeing they were improving every time they were doing it. Of course we've got a lot of beta feedback on them as well to try and determine the times we'd use. But like everything else, we just keep on testing it until we feel like we get it right."
Scenarios seem to offer shorter experiences, while the Challenge Mode caters for faster-style gameplay. Why have you decided to add shorter gameplay styles at this point?
DW: "I think those two have different reasons. Obviously, trying to finish as fast as you can in Challenge Mode is an event, a speed run. But the Scenarios are more for providing those who don't have the time for a longer dungeon run, or don't necessarily want to do that.
"They love playing their class, getting a ton of mobs and killing them, normal type mechanics but mixing it up a bit, like the stages and progressing through. First you might defend a town, then go on the offensive. There's a little story to follow, very similar to the questing experience, you get to do it with friends, it's very quick to queue for because you don't need to wait for a tank, anything like that."
Do you find that player styles and habits have changed in recent times, compared with a few years ago?
DW: "I'd say definitely, especially as the MMO genre has evolved. When vanilla World of Warcraft launched, raids were 40-person, and that was the standard, even though that was small for MMOs at the time. That's not something that would fly these days, even though people look back fondly on them."
SM: "A lot of it is that our players have all changed. We're now hooked up to social media, times have changed. Now we're way more hooked into the world by smartphones, everyone's multi-tasking a lot more. All these things have an effect on our players, they have an effect on us.
"Some of the things as we get older, we get families and so forth, so our ability to play changes and that's just natural. Fortunately with World of Warcraft no matter what your situation is in real life, there's always this awesome place to turn to, to let off some steam and have some fun."
What goes on behind the scenes when you launch an expansion?
DW: "Back in the office, our server team is amazing. They work around the clock. They'd be set up right now in the war room, where they're ready to monitor the worldwide launches, keep track of the servers, make sure everything's well. They put in a lot of effort this time.
"Unfortunately they can't come out and celebrate as the rest of us (in the UK) because they have to be there. We're very experienced with these launches now; everyone knows that the war room is within the team, it's pretty established that this is a launch day event.
SM: "Pretty much the entire team is ready if an issue comes up, we'll be able to act on it really quickly. We have tools in place to change a tremendous amount of things without players necessarily even noticing it. It's a thing where we're going to be absolutely there, if anything does come up, but we'll be there to fix things if they go wrong."
DW: "It'll be fine - flying back, hopefully we won't have to go straight into work! But there's people there ready. But today, it's all about the fans."
World of Warcraft: Mists of Pandaria is available to purchase at retail or download for PC and Mac now.