For long hubs, the first paragraph needs to be clear, concise, and interesting to hook me or I'll pass on it. Sometimes, I'll continue to the second if the first is only writer's notes to set up a chapter or whatever.
I also prefer small paragraphs, cause I'm picky (lol) and it's easier on the eyes. For fiction, especially.
In the case of long articles, there's a hint of skepticism in me that makes me wonder. If this hub is really a rant going on a wild tangent. In which, I'm a bit wary. Asking myself: Do I continue, knowing that this might not stick to the topic? Or do I skip this hub?
Often, I prefer medium size articles. However, I don't think anyone should post anything less then 200 words for a hub, unless it's poetry. At least, in my opinion.