You may have found a solution by now. If not, check this: it appears that you must have at least one page actually published in order for the missing parts of the Reader Settings to reappear. That worked for me, but I found it didn’t do me much good. I could specify my Landing Page (as my one published page) as the current home page, but I couldn’t specify my actual home page or blog page in those settings because — of course — I’m just building the site and am not ready to publish those pages yet.
I don’t know who at WordPress thought this would be a good idea or what the rationale behind it is, but I’m pretty much ready to smack somebody in the head with a bat.
