I can’t help you with the loop end, but I’m finding HotSawz anything but thin on the front end.  Quite the opposite, with extreme filter settings.  I do run in stereo, yet I don’t see anything internal to the algo that might cause phase cancellation in mono.  Maybe the detuned oscillators … but I don’t think so.

Without much modulation going on, a low MIX and/or CUTOFF below 50 or so really damps things down.  I’m finding them to be fairly interactive together.  HotSawz is dynamic to to input level, so I might check there second.  Compression might help, but I’d tend to think on the output, to preserve input triggering.