Bear in mind, I don't assume you can/should take the the Game of Thrones story concept literally to D&D's party based style.
It was more that if you recognize that "main" characters that you thought the plot was attached to couldn't die, that was a fallacy.
I see lots of good ideas, and caveats to the ideas. Which are also good to know. No single idea is perfect.
Here's a few other new ideas:
the solo session for new replacement PCs
The setup some background for a new PC that is joining the group, run a solo session, that maybe represents something he did a few years back. Or something current that will dovetail him into the party. Either way, this gives the player a chance to bond with his new PC and invest in him before he joins the party.
It also lets you give him some backstory that he earned, and maybe even new campaign information that the party didn't have when he joins.
Split up the party and do scene changes frequently
An old idea from the 2e Campaign Guidebook was to split up the party and jump from character to character. Game of Thrones basically does that, albeit in longer stretches. The main concept though, lets you run a group of players in different places, which makes them more vulnerable (as they are alone), yet cover diverging characters.
Don't overplan or script stuff out
This touches on my own method of planning sessions. I look at my PCs, players and what they want to do next and prepare plot hooks and material that they would be interested in (or are following up on from last session). I don't write up more material than I need for the current session.
In this way, if I do accidentally railroad, it is constrained to the current session, giving me a chance to correct the mistake based on what I now see the players really wanted to do.
It also means, that if the situation changes more than I expected, I'm not going to feel trapped to try to use my remaining material.
It was more that if you recognize that "main" characters that you thought the plot was attached to couldn't die, that was a fallacy.
I see lots of good ideas, and caveats to the ideas. Which are also good to know. No single idea is perfect.
Here's a few other new ideas:
the solo session for new replacement PCs
The setup some background for a new PC that is joining the group, run a solo session, that maybe represents something he did a few years back. Or something current that will dovetail him into the party. Either way, this gives the player a chance to bond with his new PC and invest in him before he joins the party.
It also lets you give him some backstory that he earned, and maybe even new campaign information that the party didn't have when he joins.
Split up the party and do scene changes frequently
An old idea from the 2e Campaign Guidebook was to split up the party and jump from character to character. Game of Thrones basically does that, albeit in longer stretches. The main concept though, lets you run a group of players in different places, which makes them more vulnerable (as they are alone), yet cover diverging characters.
Don't overplan or script stuff out
This touches on my own method of planning sessions. I look at my PCs, players and what they want to do next and prepare plot hooks and material that they would be interested in (or are following up on from last session). I don't write up more material than I need for the current session.
In this way, if I do accidentally railroad, it is constrained to the current session, giving me a chance to correct the mistake based on what I now see the players really wanted to do.
It also means, that if the situation changes more than I expected, I'm not going to feel trapped to try to use my remaining material.