It may be a little awkward but why not take finished concepts from professional designers with measurable feedback like these:
http://wikipedia.gkvasnikov.com/ http://www.wikipediaredefined.com/
Topic on Talk:Winter
Julian Claus: Pretty much what Ckoerner said below. For instance, both the examples you posted downplay or even ignore the multi-lingual facet of the site, which is arguably its most important feature.
Julian Claus: I've wondered this for most of the design projects I have participated in. And there are at least a few individual ideas in each of those designs that I find wonderful. But it is a major shift in social norms and practice to switch from the idea of designing your own solution to curating and combining solutions offered by others. In my experience it is rare to find people and fields where the latter is the norm -- while it has happened with some scientists, coders, and writers, I have yet to see it happen with design.
Ckoerner: some of those designs turn out to be excellent. Cf. user innovation in general and a certain cool cooler in particular ;)
Jorm (WMF): you're right about licensing, and one could ask those designers for an acceptable reuse license if they have any good ideas worth incorporating.
I can't speak for WMF, but as someone who has designed systems, it's never as easy do approach it from the outside (like these designers have) without multiple, deep, conversations with those who manage a product. In my experience it's more beneficial (faster, better end result, more thought out in edge cases) to have a dedicated team - with years of experience with the 'product' - learning, developing, and evolving the interface and experiences.
I could show an automaker a great concept for a car, with all the features I'd love, but then we'd end up with The Homer.
There's another aspect to this, by the way: most of those redesigns do not include licensing that would allow us to reuse the ideas.