Sencha put a hold on our certification program for a number of reasons, but as noted we'll be revisiting that decision soon.
The shortest and simplest answer is that not enough developers in our community signed up to take the test. We are exploring other ways to adjust the program to meet our developers' needs, but balancing the accessibility of the certification with the quality of the testing is actually quite difficult and time intensive.
Maybe community and forum members can help you develop new certification system by take part in designing or reviewing potential question...or in some other ways. My opinion is that it is very important and usefull for Sencha to have its certification system, specially if it is leveled like it was suggested to be in the future on Sencha's certification page. I agree that to develop certification program is very difficult, but it worths.