I Know that This is stll a work in progress But here are two Ideas that would be useful at Least to me. First I would a step by step mode like the one in papywiz, second
a button on the shoot interface that would fire the shutter manully. The reason I would like this when shooting near traffic on my manual panohead I shoot in beween passing cars and In crowds Its useful to be able to shoot the same shot a few times to get the right shot( also I got people walking right in frount of the lens). Also you might want to check out the Iphone app gps4cam at http://gps4cam.com/.
What I find intresting It generate a bar code with the gps info that you photograph and later you use to geo tag photos. I think you could use this concept to transfer other data such as xml data.