Background Item #1: If you don't recognize "West Marches" check it out here then come back.
Background Item #2: Someone who tried it with 4th edition D&D here.
I think 4E is perfectly constructed to accomodate this kind of campaign with the levelling of mosters and magic items and the push to smooth things out mechanics-wise. The accusations of being too MMO-like aren't really a negative here as the concept behind a West Marches game is very MMO-like anyway, with the important difference that the players can have a permanent impact on the world through their characters. The geography is similar to the levelled zones found in an MMORPG as well, so the whole thing fits pretty nicely.
Things to steal:
- I like placing the town across a distant ocean as a colony in a "new world". This means I can run an "anything goes" campaign when it comes to races and classes and such. I can also demand that each player describe their character's place of origin "back home" and potentially turn this into a bit of a world building exercise - potentially for some other campaign! It also means I am not tied to any publised campaign world yet I do not need to map out a civilzed continent - just a town and some wilderness
- I like the customized wandering monster tables and I think 2d6 is a good place to start.
- I like the idea of most of the placed magical treasure being wondrous items, replacing the rest with extra cash.
- I could stick with the standard D&D gods, but ... what if defining a homeland also means players can define their own deity as well - more back door world building.
- I would consider going with the inherent bonus concept from the DMG 2 and pushed in Dark Sun to remove the need for magical weapons and armor but I'm not sure that makes for a better game in this case. I still like the idea of magic items, even if the PC's are picking out their own most of the time via gold peices instead of finding them in dusty tombs.
- I can see this going well for Heroic and Paragon tiers but I'm not sure about Epic. I'm not sure that matters anyway. Maybe the sandbox extends into the planes or maybe there's a really nasty portal to the Abyss in the bottom of a dungeon in there somewhere.
- I would want to set up a wiki or Obsidian portal to run this so I would need to refamiliarize myself with those options
- Need more players to get the true feel of the thing so I would have to post up notices online and in some stores
- I usually play at home but that might not be the best way to handle it so there's another conversation and possible transportation issue
- Timing - would this take the place of what has been "game night" or would I try to work it in around my regularly scheduled games? I'm not sure, I suppose some of it depends on the response.
I already have some ideas for the map and locations and encounters, and lord knows we have enough gamers in the area. I really have to think about this.
Additional thought - There are a lot of old-schoolers too. No reason I couldn't run a second game like this in 1E/2E/BECMI/LL/BF though house rules would be an interesting discussion. Plus it would let me indulge my inner old-school DM.
Really thinking about this one...