Personally I am going to wait for some more official details. Swen is awesome but he doesn't exactly know technically how these things work.
Note this is not a dig a Swen. He called this out himself in interviews that he doesn't know for sure how this works with Steam and others. For me i will archive and delete the EA saves and will keep the EA binaries in place unless we get official word via a community update i will do an in place upgrade.
