I got my copies of the 4e preview books yesterday. I devoured Worlds & Monsters first because I was keen to read up on the new cosmology. I love it. I never really cared about the Great Wheel much. I am glad to find this thread, though, because reading through W&M sparked so many ideas that I had to get my notebook out and start writing them down as I was reading.
Some of the ideas I've got down are:
- PCs must rescue a dead relative from the Shadowfell - or perhaps just find and talk to him/her
- PCs must rescue a kidnapped child from the Feywild
- PCs accidentally stumble into another plane (either the Feywild or the Shadowfell) through one of the "thin areas" (rifts) and come across a very evil artifact thingy. They are not able to determine what it is and so they take it back with them, thinking it's just a mysterious magic item. However, wherever they go, the artifact bestows misfortune and evil on all around the PCs (but nothing bad happens to the PCs themselves). I picture them going to a village, and immediately a great storm brews and crops fail and somebody's child drops dead and stuff like that. And the villagers come to the PCs and accuse them of being responsible because these horrible things started happening as soon as they showed up ... (this will be a great way of creating conflict that isn't necessarily Good vs Evil because the villagers will most likely all be Unaligned). Hopefully the PCs would eventually figure out that it's the artifact they found and so they would then have to figure out some way of getting rid of it or destroying it, which might involve going back into whatever plane they got it from ... or perhaps a different plane altogether (maybe the Elemental Chaos).
- For higher level games, I really like the seeds of mystery and intrigue they've sown with things like the Raven Queen's forgotten name and abandoned Astral Dominion ... and how Orcus sends minions into the Astral Sea in search of her old domain in hopes of finding her name and such. I could easily see high-level PCs getting embroiled in something like that.
On a more general note, I just love all the references (and all the art pieces) to planar portals and rifts. The idea that the PCs might find access to another plane without needing a specific spell or ritual or, better yet, accidentally stumble into another plane is very exciting to me! It conjures up all sorts of exciting descriptions. I can see the PCs going into an ancient forest, at the center of which is a "thin spot" linking the world to the Feywild. And as the PCs enter that area, my description of their surroundings will subtly change, just as the surroundings do, so they may not realize that they are no longer in the normal world ... Oooh, I can hardly wait!