The S1iS is probably the best non-SLR pro-sumer camera out there, but it has its failings. The shortcomings are frustrating enough that one wonders whether Canon deliberately included them to get us to "upgrade" whenever the S2 comes out -- not that I could ever justify buying the S2, if and when.
Here are things I'd like to see improved:
1. Rubber on the grip.
2. Make the Movie start/sop button useful, like pressing it causes movie recording to start when the camera isn't in movie mode (like a shortcut button). Otherwise, I don't see the point to the movie button; just use the shutter button!
3. USB v2
4. Make the camera appear as an external drive to Windows 2000 and 98.
5. Built-in lense cap; my daughter's Pentax with 3x zoom has it, why not Canon?
6. Display optical zoom stages, just as digital zoom stages are currently displayed. For example, I would like to know when the camera's zoom is at the equivalent of 50mm, 105mm, etc. Perhaps the display could be customized, to show 2x, 3x or 5.8mm, 6.8mm, or 50mm, 105mm.
7. Eliminate the My Camera nonsense. Who cares what the start up picture and sounds are!
8. De-couple the shutter sound from the ready-to-take-a-picture sound.
9. Add the low-light focusing aid.
10. Unleash the limits of time-lapse photography. Why the 100-photo limit?
11. Fix the display bug when using 1GB memory cards. The display shows 2500/xx -- the xx means there isn't enough room to show the capacity number (3500 or so).
12. Make the Shortcut button handle more options. The one I want (change JPEG compression levels) isn't available.
13. Include TIFF format (not RAW) for highest quality images.
14. Increase the size of the LCD; the 1.5" display on this camera is too small, making it hard to compose the photograph. The size on the Gx-series is good. I like those camera with the "big" 2.5-inch displays, which allow you to use the camera to show photos to friends without squinting.
15. Make the camera bigger. Shocking, but true. Actually, all I want is more finger-grasping space to the left of the lens; right now there is a mere 1/4-inch for my fingers. Making the camera longer to the left provides space for a larger LCD screen.
16. Make the manual focusing aid larger. Right now it is a small rectangle that shows a fuzzy image. Make it full screen!
17. Move the Set button into the center of the 4-way-controller. That way the thumb doesn't need to move around as much.
18. Make settings save automatic, like on the Gx-series. I don't like having to explicitly save changed settings. If I didn't want them saved, I wouldn't have changed them in the first place.
19. Increase the resolution. Not crucial for me, because I find 3-megapixel to be the ideal compromise between quality and JPG size. But increased resolution allows higher quality photos taken with digital zoom.
20. Increase the movie resolution to true DV size: 720x350.
21. The zoom lever is too sensitive. One idea: have a menu setting that changes to Slow mode: pushing the zoom lever hard makes the zoom change slowly. A better idea: move the zoom (and the manul focus) to the lens barrel -- and with a mechanical linkage, not electronic.