As promised, here are a couple of example pictures from my terrain geneeration experiment showing how the 1.8.2 terrain can collide with the 1.7.3 terrain at the boundaries between explored and unexplored areas of the map. If you want to add examples from your own worlds, please do so.
http://www.flickr.com/photos/[email protected]/8116714141/
http://www.flickr.com/photos/[email protected]/8116714671/