Given the many times it's been requested, I'd say that they haven't implemented it because: A. They're stupid. B. They're just being mean. C. It'd be really, really hard and require messing with code that works and was written be people long gone and might be likely to cause more damage than it's possibly worth to them. Take your choice. Currently, the strategy seems to have been bolt 3rd party add-ons to the old core. Maybe, if the Shade folks keep it long enough, there will be a complete redesign and you'll get undo.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken