I can accept the critics about the Big5-rule. But there are two important reasons for EBU to do it in such a way.
First of all, what many members here are said, that they give a lot of money to EBU. But an aslo important thing is the fact, that in these bigger countries many people are watching ESC. F.e. in Germany there are around 10 millions viewers (2010 were more than 20 millions viewers). I can remember in 1996, when Germany wasn´t alloud to take part, there are less 300.000 viewers. This destroys the sum of viewers around Europe. And it´s the same in the other 4 countries.
Another fact is, that it´s a disadvantage for the Big5 countries, because most of the viewers hear the song the first time in the final. The songs, which were qualified in the semifinals are known and they have many fans, while the songs of Big5 aren´t known. So I think, it´s ok to rest this rule. But I agree, that mostly bad songs are send by the Big5-countries. This should be changed.