Am I the only person who would stab myself in the eye if litblogs started routinely posting 5,000 word critical essays? I'm betting no.
It may be "lit," but it's first and foremost a BLOG, people. There is a reason no one reads Yr Serious Lit Journal. It starts with a B.
Keep moving. Do not gawk.
A little clarification: I'm not against lengthy critical essays, but I mostly don't think blogs are the right venue for that. Five thousand words is LONG. Longer than most of the posts you might be thinking of as Really Long Posts. When I want that, I prefer to get it on paper in a magazine or, um, not at all. The idea that to say something meaningful you have to be verbose is ridiculous, like the other arguments in play here.