Switching URLs is nothing like switching shortcuts. The impact is one person on switching keyboard shortcuts, but if I switch around URLs I'm impacting hundreds (or thousands).

I'm no "pro blogger" by any means, but I have a couple of posts (that were migrated from stand-alone pages) that get a decent amount of traffic. A large portion of that traffic is from forums, other blog posts, and the like. Not from "Google juice". To change that URL means I'd have to contact all of those people - hardly workable.

I don't really care about the page rank, but I have content people find useful and I want them to continue to be able to find it.