Nowadays that manual step is preventing a lot of applications to be promoted. Right now 49 applications are eligible for promotion (maybe not all depending on that step, but most).

As there aren't many testers, the process is taking time and there is a good chance that the original developer have moved to a different platform or is no longer interested in doing anything more with his application.

Consider that if the original maintainer had already promoted the application to Testing, it's because he considered it suitable for promotion, so there is no point in requiring another manual step.