I puttered around with the idea of starting with a completely new world map for my next game, but in the end I decided that I'd simply set it in the next Age of the current campaign world. I could use the same maps and adjust and tweak them as I wanted. Not that I couldn't do that normally (I've declared a .113 phase quantum shift before) but I like the idea of having the landscape change with time. It helps with the player vs character knowledge - that land bridge might look familiar but wrong ... the player encountered it in the previous campaign, the character heard about it in a story told by his pox-ridden uncle.
There are quite a few details missing - settlements, castles, dungeons, and all that sort of thing have been stripped from the map. As each region is remapped I'll add in settlements and other details while changing the landscape as needed. For example, Area H4, Aldsburg:
Hexes are 6 miles wide making each Area around 250 miles edge to edge. This is well more than enough space for an entire campaign. The final map will have text added and all of the usual maply embelishments. Most likely I'll remove the hexes and have a separate hex overlay system (like the old Forgotten Realms). Perhaps eventually I'll post up the Atlas pdf I'm creating that has many detail. I may even create a more detailed Hex view as well for special regions.