So I'm going to be running a New Vegas sandbox campaign where almost everything is the same, save a few important changes.
1) The courier died somewhere before Benny. Actually, truly, D-E-D dead. No one knows if the platinum chip even made it to the Mojave (and neither do I at this stage).
2) Ulysses became a broken man rather than a vengeful man. He is drinking himself to death somewhere in the Mojave.
3) I am returning to the proper, real world, size of the map, so everything will happen a bit slower and most of the time the combat environment will resemble low scale frontier wars rather than continuous battle lines.
4) There is going to the a substantially larger civilian population than the computer game depicts, to be more in line with how the computer game world felt (to me at least) rather than what it was technically capable of depicting.
5) The existing quests in the world will not be on rails- they exist, but they will just act as a framework that will change based on player actions.
6) The Second Battle of Hoover Dam is happening- the forces that are propelling it are too big for it to be stopped. At the start of the campaign, it'll have a fixed date (but the players can move it up or back based on their actions and who they support- if anyone).
Any other recommendations?