There's been some discussion of Traveller on ACKS discord lately and it has me thinking.
All of the Traveller campaigns I've run or played in have been of the "crew of a single ship, small-cast" model. And Mongoose Traveller, at least, explicitly encourages this with the party skill package. But what would an open table Traveller campaign look like? How would you make that work?
If I thought adapting ACKS to open-table play would be tough, Traveller seems a whole 'nother animal.
The biggest difficulty, obviously, is ships. If there is no party-as-a-whole to own a ship, do you instead have individual players hold the leases on ships? But then what do you do in a session where no player who has a ship is present? Is this what the rules for paying for passage are for? And likewise, what do you do if multiple players with ships are present? Do you just both go to the same place, convoy-style? Do you let one ship sit idle? But then you're paying loan for something you're not using, which brings up another point - if you're a loan-holding player and you can't make a session but time passes in-universe, then what?
Maybe it's best to assume that ships sitting idle are doing boring local deliveries that just break even.
I suppose another answer to the trouble of ships would be "the party (as in the whole playerbase) is a corporation", with ships, debts, and treasury held in common. But then what if some particular session's subparty really screws up and gets the ship destroyed, or loots the party treasury?
(I suppose another solution to the ship problem is to break with tradition and embrace jump-capable small craft, allowing you to move a party but not a whole lot of gear on a much smaller budget than a typical starship)
Another difficulty - what do you do if you do have a ship-holder at a particular session, but no pilot? Here again, a seldom-used rule might be relevant: salaries for various crew positions on MgT1e page 137. The rules in Pirates of Drinax for hiring NPCs would help too. But it could get weird if the NPC part of your crew is getting paid salaries while the PC part of your crew isn't, and weirder still if you pay different PCs different rates.
Cost of Living for different PCs with different SOC stats (MgT1e page 87) also poses difficulties.
There also isn't really a good Traveller equivalent of a megadungeon. I suppose one could build an enormous wreck to explore over the course of a campaign, but megadungeons benefit from being fantastical environments which admit lots of internal variance; in a simulated "real" space, you can't do that, so it risks getting dull.
On the other hand, open table Traveller could be a lot of fun, in part on the basis of variety between planets. One of the things I liked about Traveller is that it can vary a lot adventure to adventure; it's easy to do Firefly one session, Alien the next, and Mad Max after that. And in an open table environment, with a broad set of players with different preferences and different skills, it seems like such variation might be more welcome than in a higher-continuity campaign. It might even be a good excuse to bring out some of the supplements from time to time - if you don't have a ship this session, sign on for a short tour with some mercs and do Hammer's Slammers with Striker this session, or do a stint of private eye work and bust out Agent.
But the point about salaries brought another things to mind: Boot Hill's campaign structure as described in the books, where each player is doing their own thing and you occasionally convene to resolve combats. A subsector with one or two high-tech or industrial worlds and a smattering of low-pop worlds starts to look rather like the Boot Hill campaign map, with a central "city" and a smattering of ranches, homesteads, and mines. An X-boat route is a lot like a telegraph line, while an established jump-1 trade route has a certain resemblance to a railroad (using something like warpgate stations instead of ship-mounted FTL really starts to look like a railroad, in that you have to build expensive infrastructure and only service certain spots). And like Boot Hill, Traveller admits high-volume automation of NPC generation; the process is more complicated, but the output is still simpler than most characters in D&D-type games (particularly if you prune some of the softer noncombat skills / go back to Classic Traveller). Lining up the passage of real time with the passage of game-time like in OD&D's campaign rules puts the "one week per jump" rule in a new light (I don't know that you'd really want to do 1:1 time, but it's an interesting idea. 2:1 might be more reasonable, so you can do a week in jump and a week in port per IRL week).
A lot of interesting options open up when you break the notion of "party", move to a big cast of PCs with conflicting interests, and maintain campaign-time. Multiple PC-run mercenary companies, possibly deployed against each other from time to time? Some players playing at Merchant Prince scale, some players playing individual crewmen of ships and earning salary? Cat-and-mouse games between PC leaseholders and PC jump tracers? PC pirates and smugglers who accumulate bounties vs PC bounty hunters, like Boot Hill's dynamic between lawmen and outlaws? PC belt miners claim jumping each other? Your hit the motherlode of radioactives and next thing you know you're hiring PC mercenaries to keep the PC pirates off of you.
There's a whole weird world of ways of playing when you let each player play their own subgame which interacts with other players' subgames, and it seems under-explored in tabletop games. If you don't want to deal with ship mortgages, or asteroid mining, or whatever, there's no party dragging you into dealing with that particular mechanic. On the other hand, "many players independently playing their own interacting subgames in spaaace" may have also just described EVE Online. But there's something to be said for games that have below Dunbar's Number of players and a flexible referee.
And Traveller covers two of Boot Hill's weaknesses: lack of information on economy and yields of various activities (if anything Traveller refs are spoiled for choices, across the various editions) and political difficulties around the Wild West setting.