I've always really liked the Great Wheel model of the Multiverse. No surprise of course, as I'm a big fan of Planescape. That said, there were definitely parts of the planes that didn't quite work for me. I'm curious what modifications others have made.
For me, the upper planes seemed kind of bland and boring. They were interesting but just seem kind of limited compared to Sigil and the Lower Planes.
Don't know if you know about this already, but several people have worked on tweaks to the planes which we have labelled the "Planar Renovation Project"
Here is a compiled list of the results so far
/forum/planar-renovation-project-list
some are better than others but depending on your tastes, its difficult to predict which you will enjoy more
Some of the personal ideas that I have co-opted/stolen from this list:
-Turned the Outlands into a Wild West theme (this one is REALLY non-canon but considering how bland the Outlands were, I felt a major overhaul was justified)
-Took almost all the ideas from the Bytopia thread (in my case making the two layers one of invention and one of "pioneer spirit")
-Made one layer of Arcadia a place of cities and peaceful living and another layer the battleground where the different competing ideas for "proper rulership" were fought out
-I adding a lot more themes of entrapment and paranoia to Carceri inspired largely by themes from the great TV show "The Prisoner"
Overall, I try to tie planes to themes (e.g. death, creativity, etc.) more than alignment as I finds this inspires a lot more ideas for me. (By contrast, telling me that a plane is neutral good with a slightly chaotic tendency inspires next to no ideas for me)
Darn you Wicke - you slipped in while I was typing up what turned out to be a duplicate piece of info
Glad to be of service!
My favorite renovation is probably Arcadia, though I had fun trying to tweak Ooze and Lightning. Honestly, we should do some more as they always seem to get my creative juices flowing.
I have an Obsidian Portal site (http://www.obsidianportal.com/campaigns/lord-zack-planescape) with my variations on the planes.It's mostly the Great Wheel, with some planes shuffled around and some additions, in particular from the Pathfinder cosmology (including Golarion itself).
A few highlights:
* Oerth, Toril, Krynn and Golarion, probably amongst others (Mystara, maybe? Though a version of Blackmoor closer to Dave Arneson's version is on Oerth so...) are all on one Material Plane. There are several "odd" Material Planes like fire-touched Muspelheim, air and water-touched Niflheim and at least one "Plane of Faerie".
* Paraelemental plane of mist rather than ice. Ice is a sort of "demielemental plane" along with electromagnetism.
* Several changes to the Outer Planes, including having the Beastlands be a true neutral plane (i.e. a region on or layer of the Outlands), moving Olympus over one plane to be another layer/region of Ysgard, Arborea in general in renamed Elysium and Elysium is renamed Paradise, Limbo is like a transitive plane, connecting all planes touched by chaos, etc.
Try checking out some of the threads here: /forum/planar-renovation-project-discussion-an...
We've done a number of renovations of some of less inspiring planes and have come up with some pretty interesting stuff as a result. Feel free to contribute!