Unsolicited Redesigns
ignorethecode.net
ignorethecode.net
I believe that's part of the same trend that's devaluing creative work such as design and writing.
There is the "I am improving their business by improving their design" kind of attitude which is manifested by the Dustin Curtis kind of approach. This is basically claiming that certain aesthetics are better than others and thus means better business.
Then there is the "I am improving the way the information on the page is structured to improve "legibility"" attitude, which is more about taking what already exist and structure it better.
The former is driven by ego the latter by interest. And personally I find the latter more interesting, although it's less frequent.
This echoes your (and Lukas's) sentiments.
And even if a 2-hour redesign will never fix all the problems of an existing site, it can still point out specific flaws and suggest a solution.