I have some suggestions, that would be pretty crucial to me:

1) An option to start a gallery with a thumbnail only page.

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2) An option to browse the images without any thumbnails (I know this is possible now, but I'd rather not have no thumbnails at all)

3) An option to not show any thumbnails in full screen mode. This seems pretty standard behaviour to me for a full screen option.

4) Get rid of flash altogether. This improves compatibility and (arguably) speed, and also SEO.

I am considering SimpleViewer to use for my portfolio, but it is necessary that Google can index the captions for my photos.
As far as I can see with the standard installation the captions are only embedded into the flash and xml and google can't read them.

Is there any way to embed the captions as actual text in the pages, or at least in the html?
If this is not possible yet, my request would be to implement this as soon as possible :)
That would really make it an attractive option for (professional) photographers.

Thanks in advance!