Should the Army change it's Junior NCO promotion system?

I have seen the Army Promotion Points system change twice since I have been in the Army and it doesn't seem to be doing much to help the NCO Corps.  Well thats how I see it in my branch.  I think that the Army should adopt a "Specialty Knowledge Test" like the Air Force.  My reason behind this is because I have seen far too many Soldiers get promoted to Sergeant or Staff Sergeant and know nothing about their job.  How are these NCOs supposed to lead and teach their Soldiers how to perform at their job, it that NCO doesn't even know.  I feel that this weakens the NCO Corps.  I know of one Sergeant that has been in my unit for at least 4 years, but has never done her job. Since she came to my unit as a Specialist, she has been the Battalion Command Group Secretary and updated the Battalion Facebook Page.  She knows nothing about her job and whenever she PCS's how is she supposed to teach her Soldiers?  She doesn't have any Soldiers and has caused problems in the past with NCOs conducting corrective training with their Soldiers, because she has a direct line to the CSM.  Another problem is board-babies.  There are Soldiers that don't know how to do their job or lead Soldiers, but because they study for the board so much and/or win the SOM/NCOM Board they earn their promotable status.  I have seen these board-babies win the SOM/NCOM Board one month and the following month walk in, salute and be dismissed with their promotable status.I think a "Specialty Knowledge Test" should be taken and passed as a prerequisite before going to the promotion board.  This test would be a normal fill in the blank, true/false, and multiple choice style test, with a few situational exercises.  Once the Soldier is able to pass this test, then he/she should be able to attend a promotion board.  I think that promotion boards to the rank of Sergeant should be held at the Battalion level and promotion boards to the rank of Staff Sergeant should be held at the Brigade level.  I feel that this would prevent board-babies and Soldiers not learning or performing their jobs from entering the NCO Corps.  I know that the Soldier attending the promotion board is usually up to their supervisor, but sometimes the whole buddy system comes into affect.  Your thoughts please.