I could see it being a LEGO GTA style game. Meaning the sandbox gameplay and all. Though traditionally in the LEGO games, you unlock characters and abilities as you play, which lets you explore new areas and find secrets.
Sounds like you're mainly playing the role of a cop in the LEGO City Police.
I suppose it will be more of a series of short missions/minigames. Like chasing a badguy around town. Or driving a firetruck to fires to put out. Etc.
I'd be happy if they have a "random mission" system, where it will just generate random missions for you to play out. --- Are today's games made for 1 armed, drunken kids with downs-syndrome? - krazy168 The politically correct term is "casual gamer" - wubikens