I see this as a move sideways rather than a move forward.
I don't use F-Spot, and will probably never use Shotwell. Why? because one must "import" the pictures into their proprietary file structure. What is wrong with using the already existing file system? Why must these programs impose their own idea of how the pictures should be organized? The only program I have so far used that handled this correctly was Zoom Browser on Windows. It was incomplete, but the organization it displayed was the way the pictures were organized in the file system. If you changed directories, or moved photos around outside of the program, they showed up changed the next time you ran Zoom Browser.
My father uses F-Spot. I can not convince him not to use it, and I can not convince him not to move photos around using the file system. This means he is continuously corrupting F-Spots idea of where the photos are, and he keeps calling me to help him straighten out the mess he has made.
What I want out of a photo organizing tool:
1) Use the file system to keep the files organized, and use what the user has already done! There should be no option to "import" files, just point the software at the top level directory and use it in place, the interface should be similar to Nautilus, showing the file system. Zoom Browser would be a good model for this. Doing it this way means that one is not required to use a specific tool to organize or access the pictures.
2) If you allow notes or audio comments, they should be included as part of the photo file itself. I believe that jpeg has the capability to store audio comments & notes, it would be nice if one could actually use this feature. Any other means of storing this information means this data will be lost when your tool becomes obsolete and a new tool comes out.
3) Slide shows should be able to play videos interleaved with the slides. Nearly every camera available today has the capability of recording video. I would very much like to be able to show a slide show with the slides and videos in chronological order.
I want a tool that lets me find pictures easily, setup & view slide shows easily, and does not try and take over control of my pictures.