This idea is like suggesting that Mepis and Parsix change names to become Mepix KDE Edition and Mepix GNOME Edition. While that is just an example (and a pretty bad one at that) it also illustrates the absurdity of the idea. Yes all the official Canonical distros can be referred to with the umbrella term Ubuntu but they are all different distros. Each with it's own strengths and weaknesses. To me this idea pretty much says 'let's merge 4 different distros together and call the Ubuntu X Edition'. That is like saying 'lets merge Mepis and Parsix together and create Mepix KDE and GNOME Editions'. Kubuntu and Xubuntu are each individual and independent distributions. Just like Linux Mint. Would you consider changing the name of Linux Mint to Ubuntu Mint Edition just because it too is based on Ubuntu? I know I wouldn't.