As someone who is in the market for one of these units, I am currently working through the above document, which I realise is still a work in progress.   (RME's practice of producing comprehensive manuals and placing them on-line sets it ahead of many of its competitors),

TotalMix is a simple concept which is capable of great complexity.  (Its one of the reasons I favour RME products.)  Adding FX brings this to a new level.  In trying to understand the innovations, I am having some difficulty at present in clearly understanding what has been implemented.  (And of course, I do not have an actual BabyFace on which to experiment and clarify what actually happens ...)

I note that the block diagram (p.41) appears to be presently little changed from the previous edition, eg., for FF400.  The new LC EQ only appears in the supplementary 'Loop back' diagram on p.59.   There is no diagram that clearly explains the Reverb and Echo facility, and how the feed to the FX-in bus is derived.  (Is it mono for each channel and the FX input is only mono, or if it is stereo, is it taken from the "panpot" output of the 'loudest' channel?).  Likewise diagrams to explain how the Trim Gain control logic works, where LC EQ is placed in the input channel, and so on.  (And even in the present design, where switching for Solo versus Mute takes place in the audio path?).

I would like to suggest that consideration be given to the inclusion of more TotalMix FX information in diagrammatic form.  I realise there is a need for a simple 'starting-point' diagram, but there is also a need to have a 'complete' diagram to depict audio flow, as well as 'sectional' diagrams to deal with particular facilities like Loopback, Reverb and Trim Gain.  I have been trying to construct my own personal block diagram to help understand TotalMix FX, but I am still finding some gaps in the text.

One observation I would like to make is that I think block/signal-flow/logic diagrams are very useful, especially in the context of a multilingual market.  A picture is worth a thousand words, and like the old silent films, pictures don't need to be translated.