Originally posted by bluewaterrider
As I said before, the answer to this question is two-fold.The first is that there are good in-story reasons. Superman is under control. Someone else needs to free him. All other immediately available heroes are potential pawns; Wonder Woman is the only one equipped under the story's circumstances to save Superman.
The second answer, however, is the fourth-wall answer, and is what made your question interesting. Rucka chose to end the "Superman" storyline, as you call it, in a Wonder Woman title, in order to boost sales.
That can be stated as the reason for nearly everything that happens in the industry, of course, but this is one of the few times where that strategy worked, and worked WELL.
So well, in fact, that you can demonstrate the fact of increased sales via chart, as one poster on now-gone DC Comics Message Boards was kind enough to do for viewers on that forum.The figures that back up the chart can be found via a number of archives and sources. In all likelihood I myself will post them if allowed. In the meantime, examine the attachment. Note the trend of the average comic is to start high and drop to a stable but low finishing point. Typically, a high peak is found when a comic is re-numbered. Note how high Wonder Woman Volume 3, #1 is, for instance. (People LOVE to collect #1s.)
Note however, the second highest peak in that period, which spans a length of several YEARS, is the Superman/Wonder Woman fight issue, Wonder Woman #219, Volume 2. More remarkably than THAT, though, note that sales remained SEVERAL THOUSAND units higher than what they had been before that point, and stayed that way until the end of Rucka's run.
That couldn't be done in a superman comic, why? Characters get mind-controlled a lot in comics and it wasn't the first moment that superman got mind-controlled either. In other words it was just to give wonder woman fans a story where she looks good against superman. I remember wonder woman fangirls screaming murder when gail simone said that wonder woman is weaker than superman in strength.