So how come, that far fewer people can role out such a feature easily, while MS cannot? "No need to offer support." I hear you say, but is that really it? If the feature just works well, because it has been developed well, and does not cause many if any support cases, then that point would be invalid. Lets take for example XFCE panels. I can stick them wherever I like. If there is a problem, then it is with panels themselves, not with their position. And for things like deskbar mode I can write a wiki article and point people to that.
I think support shouldn't be such an issue, if things are well done. And of course you can always have less-power users, who will have some issue. But they will have issues anyway, if not with a deskbar kind of thing, then with some other thing. Should MS therefore strip their OS of all features? It seems ridiculous. Why not release a "Windows for computer illiterate" version then and keep a capable version?