I'm not advocating for sub-folders or sub-notebooks against tags. I think they are complimentary. Tags are fantastic for topics, but sometimes information needs more structure (think of libraries - they use tagging AND categorization). Featurewise, sub-folders or sub-notebooks will not result in added complexity, as people who only use tags and finds them sufficient can continue to use their Evenote this way and it will still be simple (just forget about folders). E.g. we now have sub-tags. Does it result in more complexity? BUT for people who prefer to use only folders/subfolders or a combination of tagging and folders/subfolders it would be very important. Regarding GTD, a simple example, for every project I like to have my supported materials ready and accessible with just a couple of clicks. In Evernote 2 I had a sub-folder Support materials for each of my projects, containing notes and stuff for the project. You can do it with tags, of course, but if you have 30 projects or more, and just want to see support materials for a certain project, you will either have LOTS of tags or LOTS of notebooks or just complete mess of everything... And, believe me, deciding which tags and notebooks to select to be able to see you next actions in a certain context for a certain project, based on the present system of tags is everything but simple (the same goes for the saved searches, which can help to make a process faster, but result in more clutter).