I have, for example, the M4 character and all his poses, clothing, hair and texture presets all together in one folder structure so I know exactly where it’s at. Will I be able to keep such a manually created folder structure with the new version of DS? I prefer full manual control of my content - logically organized, easy to find, and as simple as possible.
Yes but you won’t be able to use product metadata and you’ll need to manually reorganize everytime you update a product (which happens more often than it should these days - I think DAZ is a bit swamped).
The recommended approach (which even some die-hard compulsive self-organizers have moved to) is to leave files & folders where they are and use categories to organize things any way you like. That allows you to benefit from the metadata, it insulates you from product updates and you can literally organize any way you like, even using multiple methods.
There are a couple of good tutorials on categorization (http://www.daz3d.com/forums/viewthread/306/) and you can check the link in my sig if you ever get interested in metadata (which you might be, if you’re a compulsive organizer).