It would be great if we could reorder cards. Streams should be viewable as "chrono order" and as "final order", so readers could easily switch back and forth. Streams would ideally default to "final order".
I'm +1 on being able to re-order cards.
When I originally conceived of ThoughtStreams, it never occurred to me you'd want to re-order cards. My original thinking was that each stream would be a sequence of thoughts.
However, enough people seem to be interested in re-ordering cards that I'm giving it thought (although it will take quite a bit of thought, particularly from a UI point of view).
I think, personally, if I had things I wanted to re-order I'd make child streams for them rather than individual cards. But of course, re-ordering of child streams doesn't exist yet either.