My opinion: There should not be such a list - only creates confusion and unhappiness when the company expands (link Airlink) and the list does not really make sense with the different AC types, etc.
What caused the nashing of teeth and the tearing of cloth was the fact that the seniotity list was not followed. I am not saying seniority is ideal, but its a whole lot better than not having a system.
Are there airlines with different ac types running a seniority list that works - without complaints?
Yes, pretty much every big airline in the world. The only people that don't like the system are those that dont like being at the bottom of the list.
......but still take direct entry commands successfully.
DEC's have nothing to do with seniority. If there are no suitable pilots for promotion inside the company, of course you taking in DEC's. Just they fit onto the bottom of there seniority system.
Not sure what the gripe with seniority is, as its a system that rewards loyalty to the company.