How about Spoories introducing a system where you could get command after say, 5 years, in the best interest of the airline of course. That way you could get the ratio of captains of colour quickly remedied, all under the guise of competency and "most suitable pilots", of course.
Interesting concept with one major flaw. Most airlines are approximately 50% Captain/50% First Officer. To upgrade after 5 years, the airline would essentially have to double in size every five years or suffer extreme attrition at the top.