Hurray! They certainly have a lot of irons in the fire at the moment. Hopefully some of these things will be ready for the Summer Event, but I'm not really holding my breath or anything.
Anywho, let's see...
We know that the Boardwalk will be open soon and that's it got pirates. Reportedly JK and some of the other devs have mentioned the word Kraken during their Friday zOMG get togethers.
Deadman's Pass will be expanded upon. We got a preview of that with the 2009 Halloween Event. There's a thread up now with concept art for the area's boss character.
The Coliseum is being revamped. Four different types of mini-games, three skill levels for each. Will probably be adding 12 badges because of this.
Wheee!
Here are some useful threads regarding behind the scene's stuff, upcoming stuff and what not.
zOMG! Behind the Scenes and Art CompilationScreenshot of Barton Coliseum from Fanime 2010 panelzOMG! concepts from Fanime 2010 (image heavy)