Some of the strengths of Eurorack for sound mangling would be complex, audio rate modulation. A simple example would be plugging an oscillator into the frequency modulation of a filter cutoff. You can get a lot deeper down the rabit hole than that of course... especially with digital modules that weren't intended to be modulated at audio rates... but you do anyways :)
Another idea would be an interface like the Expert Sleeper's ES9. That opens a lot of options for getting sounds from your DAW into your Eurorack and back out (to record them). It will also allow for some hybridization between your systems as well as allowing you to modulate virtual instruments and effects with your Eurorack.
Oh, and check out using some filter banks and stereo filters like Make Noise's QPAS, envelope followers, and sample and hold units.