OMG - I've been using Octoprint on a Pi for the longest time, and just lately figured out that the source of this 'globbing' problem on complex parts seems to be the communication link between the Pi and the Ramps controller board.  On tight curves, the hot end would hesitate slightly - great genius that I am, it took me this long to get the idea that with a Bowden extruder that's likely to cause at least some level of glob.  I sort of proved this by putting the same .gcode file on an SD card, and the resulting print looks noticeably smoother.  This could also explain why some of the more delicate prints would get knocked over, as a collision between the hot end and the part is a bad thing.

I could probably live with using the SD card and the Ramps controller, but I've become very fond of the remote control aspect of Octoprint.  So a Duet WiFi controller and associated Panel Due are on the way.  Time for brain surgery.  Apparently this is a fairly painless process, as others have done this retrofit successfully.  The hot trick seems to be knowing to modify the resistors in the optical end stop boards in order to interface with the Duet properly.