Kevin and Sasha are completed, so they won't be experiencing the Extended Cut unless I restart them completely (which doesn't seem like a bad idea, but it will be a long time before I get around to doing that). Riley finished the Cronos Station assault, but still has the "restart mission" save, so she should be able to experience the EC first. John just finished Horizon, and I'm not sure where Lando is, but Jynelle is still early in the game.
I've yet to start Tasha, Patrick, Mike, or Angel, so that shouldn't be a problem, either. I guess the biggest problem will be for those who haven't played multi-player on a regular basis and let their Galactic Readiness slip. Frankly, this wouldn't be too bad, because that may result in different scenes for the expanded ending. It should be interesting to see how this all turns out. Bioware didn't have to do this, but I'm glad that they are. Hopefully it will leave me with a less bitter taste in my mouth when all is said and done.