I think if Lucasarts is looking on messageboards for game design ideas, thats pretty bad. Usually a designer probably has a clear concept of what he will do and what the characters will be like in the game.
I personally don't see too much Mo in the girl in the trailer. Because she is clumsy with bikes and what not. The game producer probably has a very good concept of how that character (who probably isn't Mo) will act and how that will fit into the game's story.
Even though that was pretty preliminary the scenes shown were obviously FMV. If they have FMV done of the game they probably have a good bit of the game felshed out already....Lucasarts usually doesn't show its games off until they are pretty far along in production already. I remember the first previews of Grim Fandango in Computer gaming world had screenshots of locals ranging from Manny's office...to the boat in the middle of the game....and then to the final temple at the end of the game. The game's story and feel was already complete. It took a while for it to come out, but the game was practically finished in the design aspect.
I image Full Throttle 2 is also further along in production then one might think, and that not much will change as we get more information.
BTW Slovenija forever!