Road placement can knock one or two players out in the first round or two, on random boards with unfortunate initial placement and four players. Probably the weakest thing about the game—sometimes you pick the best spots available at placement, but are effectively doomed from the start unless other players screw up really badly, and it's that extremely bad kind of losing-early where you're technically still playing but also can't do much. Like, if you want to make other people's experience as bad as yours, you can just give resources to someone to play kingmaker rather than futilely trying to build stuff, which is surely more entertaining than doing nothing, but is also not exactly a positive kind of entertainment.
Playing with three mostly fixes it, but then there are fewer people to trade with. Using a set, balanced board layout can help, but IMO gets kinda boring.
My family tends to play with the 5-6 player expansion with only four players, which I think tends to mitigate your mentioned issue somewhat; on the other hand, having that much space also leads to a lot of 'solo play', where you don't need to trade as much as everyone can generally get the resources they need and you're just waiting for the resources. The expansion-with-four-players certainly feels less cut-throat/competitive, for good or bad.
I generally see experienced players manage to at least scrape out a mediocre starting spot, no matter how bad their turn is. But new players can pick a bad spot, which is like the worst possibility because it leads to a bad first experience for someone who doesn’t even know how to mitigate it or why their pick was bad (I mean you try to coach them but sometimes people don’t listen, etc).
It's a bit of fun to see the losing position early and become a nuisance. I can't normally role play or act, but catch me knowing I have no recovery in Catan...
My favorite style of play is to dedicate the entire game to screwing over the one player that has no sense humor. Even at the expense of actually winning the game.
The reactions to doing moves that only hurt them, which otherwise have no personal gain and often cost you future opportunity, are absolutely priceless.
Cities & Knights is pretty good too, quite more dynamic, and can combine with Seafarers.
Playing with Helpers also modifies the game enough to try more strategies if you are stuck. The "Marianne" helper, for example, can really be a saving grace during a sequence of bad rolls for you.
Cities & Knights makes the game richer, absolutely recommended for advanced board game players. I heard that this was actually the original game as he designed it, but the publisher requested a more beginner friendly version, leading to the base game as we know it.
