From what I understand you can edit using the Quicktime files, it's for the finishing and if you want to get back to the RAW that you need Cineform stuff. Or did I miss something?
4K in effects is a nightmare as most of the time you don't just deal with 2-3 layers. Even in 2K it will be heavy to move and to keep interactivity in GUI, except if you are using proxies.