YES to National Seniority list.
Just because you think it would be hard to establish is not the reason to not do it. It should be a goal. If a pilot at Airline A wants to work at Airline C or D due to QOL or a base closer to his home then he should be allowed to do that. Restrictions would have to put in place to protect guys at Airline C or D but there is no reason why someone should have to commute from California to NYC to fly for a living.