There is a vivid discussion between Stevan Harnad, Peter Suber and Peter Murray-Rust about the re-use of Open Access contributions in their weblogs, see
http://www.earlham.edu/~peters/fos/2007/10/more-on-removing-permission-barriers_16.html

Ms MacCallum has shown in her article that the relevant definitions of "Open Access" clearly allow re-use and that PLoS' CC-BY license is the most appropriate way to keep the contributions "open".

For more arguments see e.g.
http://archiv.twoday.net/stories/4351742/

Although it is true that we "don't know yet what innovation means with regards to the full text of an article" there are some good reasons we can mention already today.

Mass media (which are falling under commercial use) can spread scientific knowledge and bring it to the citizen who needs it or are interested in it.

Wikimedia Foundation Board Member Erik Moeller has argued convincingly at
http://freedomdefined.org/Licenses/NC
that CC-NC excludes the world of Wikimedia projects (e.g. Wikipedia or Wikibooks).

MsMacCallum has mentioned the possibility to make translations (which can give a chance for developing countries).

If derivative works are allowed data lists or the body of the article could be enriched by other scholars, e.g. in a wiki-like environment.

For data-mining see the position of Peter Murray-Rust quoted in the weblog entry above.

In 2004 Gass et al. have mentioned the LOCKSS projects as a reason for the re-use possibilities of the PLoS license choice at
http://dx.doi.org/10.1371/journal.pbio.0020228

I would like to see PLoS collecting more such arguments in the future.