I can't really say anything constructive about the school/city theme because I've never actually had any city sets.
I know this is generally talked about a lot but I didn't see it mentioned here so:
I want more space themes. I know there's Alien Conquest right now but it's only real relation to space is some aliens and flying saucers. When I think "space" I'm thinking of giant fucking spaceships
. When someone says "MOTHERSHIP", a one-seat saucer
is not what comes to mind. Now I'm not saying that this is something lego should do, but it's definitely something that I would like them to do and that is plausible (even though star wars will probably still sell more
As far as what lego should do, I don't fucking know, I live with my mom.