I have I think 14 or 15 different versions of Traveller. From classic first edition, to tiny fan-based Traveller Hero and Action! System Traveller. Although these versions give me a wide variety of rules and systems, I still use many other games to provide character and flavor. Games like Theatrix, Mekton Zeta, Last Exodus, and High Colonies. So what systems and settings influence your Traveller settings and series?
As an example, Theatrix had a great system for dealing with very slow skill progression that seemed to work really well with classic Traveller back in the day.