In reply to Antony Smith.

I'm not sure they even understand UI or put much emphasis on it. While WordPress is usable and has certainly improved, a lot of the UI aspects aren't that great. My gosh, consider how WP comments work... how long have they been awful? The media library?

They seem a bit like Google... make it function and then maybe someday, someone gets around to making the UI better (even then, not often great, just better).