Some people here imagine that a seniority system protects them from being abused by management, however I'm sure we all can think of a number of fellow pilots who have still been screwed over in other ways despite the existance of secure seniority lists, cr@p simm/check rides being only one example of how easy this is to happen.
The problem with seniority lists , like any military hierachy, is that it also allow's completely dysfunctional and personality deficient people ( even though they may be technically qualified) to get into positions of enormous power and authority,( enabling them to make everyone else's life unpleasant), simply because they are in the system.