Admittedly I've only looked at one or two Chaos Scar adventures, but is the paradigm actually increasing in levels now? I only saw very low level stuff, but if it does increase with Keep on the Chaos Scar and future adventures then awesome. Chaos Scar could end up being the love child of APs and Dungeon Delve, and more useful than either, easy enough to drop in any game but meaty enough to make it worth while.
The idea of 3-or-4-part adventures is also really appealing and seems the MOST ideal for me. I have my own homebrew with my own large and small plots, and adapting one adventure from APs fails to readily give me adequate framework for a larger story (the equivalent of multiple, related adventures) without adopting some, if not all, of the AP's larger themes. Maybe that's not entirely true, but it requires a lot of forethought and finagling on my part. I'd prefer a trilogy or quartet of adventures, like the Slavelords for 4e, wherein there is a story that could be adapted to my world but, even more importantly, stretched and connected beyond the ken of just one adventure to bring more memorable oomph.