Robert Schumann's symphonic oeuvre has been plagued for decades by complaints about both its unattractive orchestration and lack of thematic coherence. Felix von Weingartner (1897-1942) was one of the first conductors to voice his displeasure with Schumann's dull orchestration, which he felt bordered on tedium. Leonard Bernstein (1918-1990) believed that a truly good orchestra was needed to perform Schumann properly (and one might add, a truly good conductor as well...)
Nikolaus Harnoncourt (1929-2016), equally a master of his craft, always resisted the notion that Schumann was a poor orchestrator. However, he—and in this respect he did not differ from Bernstein's view—held that the orchestral balance needed to be handled with utmost care. In his words: 'In der Instrumentation der Symphonien und der Großwerke zieht er alle Register, die überhaupt nur denkbar sind, um die Situationen wirklich gegeneinander zu kontrastieren. Wenn man den Eindruck eines Problems mit der Instrumentation hat, is das ein Problem der Wiedergabe, aber nicht das Problem der Komposition. Komponiert ist es perfekt.' With which, as far as the latter is concerned, Harnoncourt set aside the question of whether coherence was lacking or not.
So according to Harnoncourt, the fault lies with the conductor (and consequently the orchestra) and not with the composer. I fear that Marek Janowski has not taken this view sufficiently to heart, for the impression that continually imposes itself under his direction is that of an overly thick texture that moreover manifests itself throughout all sections of the orchestra. Though it is possible that the recording technique also played a role in this. The orchestral balance is equally unsatisfactory, the instrumental solos (woodwinds!) lack the required incisiveness, and it is sometimes difficult to discern the instrumental brilliance of the Dresdner Philharmonie in the middle voices. The sense of structure is certainly sound, undoubtedly also shaped by Janowski's extensive experience with the major orchestral and operatic repertoire.
My final conclusion can only be that you need not place this edition at the top of your wish list. Fortunately, there are considerably better alternatives!