It's funny, because screen height shouldn't affect "readability" (other than making you scroll more often), but with these large-font blogs/sites, they give me a certain feeling of "claustrophobia" -- that I can't see a couple paragraphs' worth to come, or can't see the last couple paragraphs I read.

I think it might be that it prevents me from being able to scan content easily, the way you can on a printed page, where you can quickly skip to the part you can tell is relevant to you.