It looks as if the upcoming Minecraft 1.7 changes will dramatically alter the way world generation occurs, almost bringing it back to a hybrid of 1.7.3-BETA and the current system (1.8 introduced the large, almost infinite oceans, and other changes that reduced variability). Interestingly, 1.7-release will now place low moisture biomes next to each other and vice-versa, maintaining a world that makes a little bit more sense geographically speaking. Oceans have also been shrunk, and it appears that they're also peppered with regular islands.
Now, the obvious point is that updating the current world to 1.7 when it's finally released will break world boundaries and introduce jagged terrain in parts much like what's already happened in our existing world. Thus, we have two options: 1) Create a new world to begin building anew on or 2) use our existing world and just setup a portal that transports us a significant distance away from spawn for access to new features and biomes.
If we go with #1, I'll implement it in Multiverse so you'll have access to all of your existing materials and be able to shuttle them into the new world. This way, little is lost except for the structures we've built over time.
If we go with #2, I may see about generating a larger area of chunks to encompass much of what we've already done and then surround everything that has been generated with bedrock so it has a more aesthetic appeal as a kind of boundary with the new terrain being generated beyond...
Thoughts?