It's funny that this poll has appeared as I just last week needed to deal with this exact same thing.
I would love to see it in Scribus! Even if it's an implementation of something that already exists how can it hurt to have such a major program bring it to the masses and have that many more people's eyes on it, using it, and finding bugs and suggestions?
For me I do a lot of work in Scribus, but I ended up having to do a booklet and went back to InDesign as it includes all that I need for imposition. This would be one of the final major nails in the coffin of InDesign if Scribus included it.