BelArg,
You defeat your own arguements. If you are trying to make it a SAFETY thing about promotion, then you have a problem with your training department.
The reality is that you simply use an arbitrary standard, (seniority + x number of hours etc.) for promotion, and then you get to TRY.
The promotion is not automatic at ANY airline (atleast in the USA, though your example of the x president proves quite the opposit problem without seniorit, even if you did block it that one time) , if you feel that the captains are not qualified, then you are argueing about training standards, not seniority.
So you have blown your own arguements out of the water. Unfortunately seniority, though not perfect removes ALL of those outside pressures and makes upgrade to captain simply a test of skills, as it should be, and not a test of skills + political connections, as it absolutely should NOT be.
Cheers
Wino