I *think* (but at this point am not sure) that I am saying that the Third Imperium is relatively light at this point (even fungible), and is relatively unentangled with the rest of the materials which make up Proto-Traveller.
I *don't think* I'm trying to say anything more than that.
Cool. Thanks.
The only bump I have with this is, for example, you bringing up Space Vikings as an example of a possible Proto-Traveller type setting. But there is nothing like the Imperium in the Space Vikings setting. (An entity like The Imperum would break a setting like Space Vikings.)
However, all the elements in Books 1-3 (the implied setting material) would function quite comfortable in the Space Vikings setting.
My own thinking is:
1) There is "original Traveller" (Books 1-3) which has awesome implied setting material that can still grow out countless ways (and must, in fact, since the SF elements in Books 1-3 are incredibly light!).
2) And then there is Proto-Traveller, which is an awesome, lightly sketched setting of a stretch of space called The Spinward Marches at the edge of an even more lightly sketched thing called The Third Imperium.
3) And then ther is everything after, where the elements becomes heavily focused on The Imperium, high level politics, beuracracy, military issues, and, at the SF end of things, The Ancients and their genetic manipulations.
In (2) the setting, even though lightly sketched, is still up for grabs by the Referee, is a rough and tumble frontier, and there's lots of room for all sorts of SF weirdness* if the Referee wants it. In (3) the Imperium enforces a peace across the Spinward Marches, the SF elements of weirdness are almost non-existent, and the setting becomes less of a frontier full of golden age SF adventures and seems like a setting focused more on late 20th Century Cold War geopolitical issues and trade issues.
So, that's where I'm bumping. But, again, not challenging. This is a project you are pursuing. I was just curious about what you're thinking about this.
* SF Weirdness: See Jack Vance, Poul Anderson, E.C. Tubbs, Alfred Bester, and others.