I didn´t care about the themes as they perfectly fitted my idea but I think that in the future some could be given for inspiration but nobody should be made to stick to the themes. They should be themes only as everything else would be too much restriction.
I think the ticker with ca 3h updates is perfect.
I would prefer a shorter time for the contest like 8hours or something like that as one usually doesn´t have two complete days to work on a project. Or one could give about one week but then with a lot less updates of the ticker due to school, jobs, whatever.

But it was a very nice experience and I´ve got another finished project now