Seniority only works for the Company and weak pilots.
Seniority is a terrible system for an airline to use for deciding who will get a promotion.
Rather short-sighted views, methinks, although I note the implied smile in the latter post.
First have a strong union so that most of the time, most of the people, are kept reasonably honest in their employment dealings.
Second, so far as a command upgrade is concerned, seniority only means that Pilot Bloggs gets to have a run at command training in a reasonably predictable sequence .. unless things have changed dreadfully, it doesn't necessarily mean that he/she gets the guernsey, only the opportunity. He/she still has to get over the various bars in the vaulting exercises ... I would be surprised if folk get to have more than 2-3 attempts before they either get the bullet or permanent F/O status ..
As to better ways of doing business .. of course there would be .. provided that everyone were morally honourable .. but that remains a problem.