Regarding arrow (cursor) keys, I have now had an opportunity to do more testing with the HHKB Pro 2 and KeyReMap4MacBook software for the Mac. Using the DIP switches on the keyboard, I can remap the left Command (Diamond) key to an extra Fn key, so that I can control the cursor diamond from either the left or the right. Moreover, using the software, I have 14 built-in choices for arrow (cursor) keys, including choices of modifiers and WASD, EXSD, RVDF, ESDF, and IJKL. I could write even more custom choices by modifying the XML configuration file.
Although I rather like Control_L+IKJL, I have mostly been using the default Fn+[/;'. After using the HHKB Pro 2 for only a few days, I now prefer it over the Leopold FC660C and even my IBM SSK. This surprised me, because I thought I would have had trouble adjusting to the differences in layout and the absence of dedicated arrow keys, but the HHKB Pro 2 is amazingly intuitive. Its styling, minimalism, feel, sound, and efficiency combine to make this keyboard a joy to use.