From allkpop: http://www.allkpop.com/index.php/full_story/wgm_pds_blames_everyone_but_themselves/
Here comes the official explanation from the We Got Married PDs on their swift decision to boot out all the season 4 couples. "Marriage isn't dating!" After an emergency meeting this past weekend, the PDs came to the conclusion that the existing 4 couples of Jung Hyung Don - Tae Yeon, Kangin - Lee Yoon Ji, JunJin - Lee Si Young and Shin Sung Rok - Kim Shin Young weren't able to give an accurate portrayal of a realistic married life. Their knee-jerk reaction to the falling ratings will see all 4 couples leaving the show on 3rd May together.
The production team also expressed their new concept for the 2 new incoming couples, "The new couples will be able to give an accurate portrayal of actual married life. In other words, although the current 4 couples are having a make-believe marriage, they aren't able to give a sense of realism at all. It feels more like they are dating and getting to know each other rather than living as a married couple even if its make-believe."
We Got Married had started out as a program where celebrities get together to live out a make-believe marriage. But couples that have recently got on the show seems to be more concerned with portraying an image or putting on a show rather than showing what married couples do in real life. Although there are the usual missions, there are no more squabbling couples like Crown J - Seo In Young, Jung Hyung Don - Saori.
The 2 couples mentioned would get mad at each other at the simplest of things and sometimes even frustrate watching viewers, but yet they give the accurate portrayal of a real-life couple. Some feel that the recent couples on the show seemed to be more concerned about how their image would come out on the show rather than letting their real personalities show out. This ultimately makes it very unrealistic and alienating viewers in the process. But ask yourself one question, my dear PDs, who decided on making Kangin - Lee Yoon Ji a poor college couple from the start?
And thus We Got Married has decided to go back to the show's original objective. Existing couples will not be given any farewell misson and just exit the show directly. The reason given was couples who are divorced don't exactly go on a farewell vacation.
In summary, they are just pushing all the blame to the couples instead of blaming themselves for changing this and that. 1 of the new couples have already been announced today and they are Kim Young Jun of SG Wannabe and actress Hwang Jung Eum. They are a real-life couple who have been dating for 3 years and it remains to be seen whether they can keep the show afloat because this is probably the last throw of the dice. Jessica of Girls' Generation and G-Dragon of Big Bang have been suggested as shown here but it's just a stupid RUMOR since they aren't dating in real life.