Let's say if I would scatter masks - not color textures - and make sure these have some randomness to them enough I guess the idea would certainly deliver good results, even if blending the texture border would produce blurriness. The mask would be used for nodes which would certainly 'breakup' the look.
The problem in my case is simply that noises do not produce the patterns i'm after. If the tool was present I would use it, since it's not people smarter than me will probably able to mimic this to some extent BUT there's a significant difference between a math-based solution that requires deep knowledge of present tools, math nodes AND the pitfalls and a ready-to-go node that does all of this plus some more on the other hand. And saves you and the client hours that you then can put into other areas of the job or get the job done quicker. If TG wants to be accessible there's no way around some user friendly and versatile low-entry tools.
This is in no way meant to be snarky but were such tools available the forum wouldn't probably need multi-paged threads about blocky rock displacements with 10 different ways how to get the look (or not). It would be a simple PS job to produce some masks and there you go. I don't mean to diminish the amazing stuff people produce and discuss - I really do love it - I just question the fact that in TG you often need to sort of reinvent the wheel to get somewhere.
Sorry for the off-topic semi-rant but I spent too many hours today not getting what I was after
Thanks for all the suggestions!