'Order of importance' type field
Could you use "tabledrag", the code draggableviews uses to do dragging? It is basically javascript acting on an html table, with a weights column to remember the order.

Have a look at how the block module uses it (but bear in mind block is more complex because it has multiple regions to manage).

For tabledrag to work you need your questions in the form of a html table, which you then extend using the render array "#type" = "tabledrag". It is possible to configure tabledrag in Javascript, too.