I doubt (rightly so) things will change with regards to airlines using seniority systems. Just to ask a counter question, why should a skipper who got her/his command after 3 years of SH flying be able to jump above somebody who has been a FO for 16 years flying SH and LH with thousands of hours under her/his belt who just hasn't got her/his command because people generally stick with his career airline?
There is no fair system. However from the moment anybody joins the aviation word all the facts are out there. Some choose to join a stable legacy career airline with a seniority system, some choose to only fly regional props because they live close to base, some choose to fly flow fares or happy holiday people because they don't want to be a number and they love the smaller bases. All these come with risk and benefits. The risk if you join a charter company is it might not last you until the end of your career and you could end up seeing a bankruptcy when you are in the twilight of your career. Joining the legacy career airline you know you won't be a training captain as fast as the person choosing the charter company but you are much more likely to see your retirement with that airline.
This discussion will always be returning. The pilots working for a seniority system defending it and the pilots who have come to realise they made the wrong career path choice criticising it.