I've just watched the "K7 in action" video by Guy Michelmore as well as a few others about K14S in general. Frankly, after the initial excitement, I'm more and more underwhelmed by the changes although I will probably update in the future. I'm still on K12 + Noire at the moment.
The new categories browser is nice and seems quite useful, however, I still have and regularly use a lot more open Kontakt libraries than Kontakt Player ones. From what I've seen, the new browser has the options for displaying and organizing OF libraries, but they seem a bit messy and cluttered to me. I'm hoping that QuickLaunch won't go away anytime soon. Also, the generic folder icons amongst all those shining thumbnails look rather ugly.
Speaking of KFL2, the new orchestral category does sound much better than the legacy one. However, I've also noticed that seems to be a large quantity of older content. For example, I could swear that the choir category is identical, just with a new GUI and a few additional controls. I even spotted a few synth and acoustic sounds that have the same preset names as they had in the original KFL. It looks like they've done something similar in Guitar Rig 6 - most of the content is sonically the same but with a new facelift. BTW, as gorgeous and modern as these new wallpapers in KFL2 look, at the same time, they feel a bit infantile for an industry-standard product (IMO).
All in all, I almost certainly won't update before the next SoS sale. There are some nice new features in K7 and K14, but I was expecting a bit more. Of course, I'm sure that there are a lot of "under the hood" improvements in K7 that will show over time.