Can you let Preview (the app) cycle through anything? This is related to this question:

How to start a slideshow on the Mac super quick and easy?

Basically, I wonder why even in Snow Leopard, I double click on a photo in Finder, and Preview will show that photo, but no arrow key can let me see the next photo in the folder?   Is there a way at all?  Or will the next version of Mac OS X add it, I wonder -- is it that counter-intuitive to show the next one?
As more or less already answered in the question you linked to, you can get the effect you want by 


selecting the first file, pressing Space to open Quick Look and use the cursor key to jump to the next one
selecting all the relevant files (pictures) and pressing Space to enter Quick Look
selecting all the relevant files (pictures) and pressing &#x2318;+O to open them in one Preview window
command-doubleclicking the folder containing the pictures to open a new finder window followed by &#x2318;+4 to switch the new window to Coverflow mode
command-doubleclicking the folder containing the pictures to open a new finder window followed by &#x2318;+3 to switch the new window to Column mode and just step through the files to get the content displyed in preview mode in the last column.


Given the different options already available to get the desired result, do we really need another one?

PS: Technically speaking, Preview.app is just an application able to display pictures and PDFs. It doesn't know anything about a next file in a folder.