This is mostly due to a kind of 'delirium' that runs through them, a disjointed set of motives that often resemble irregular and undefined tonal order.
This really is a great description of Mahler. Thanks for putting that down as it describes what I've felt about him but haven't had the ability to properly formulate.
Because of that "disjointedness", Mahler often leaves me cold. Whereas I love Beethoven and Wagner -- Mahler leaves me fairly unmoved. I can intellectually appreciate it but somehow it never resonates like Beethoven or Wagner does.
this territory is moderated