I'm having exactly the same issue using S3D 4.1.2. THe part prints smoothly but the ooze shield printing feels like the machine is going to disintegrate! Firmware is Sailfish.
The reason is definitely the GCode which is printing lots of small lines rather than a smooth arc. It also slows down the printing compared to drawing arcs. Even longer lines would be better. The waterfall shape sounds like the bottom of the Niagara Falls!
Could this be considered for a fix in the next version?
Re: Harsh vibration on ooze shield but not part
Further to my previous post, I was using Contour, not Waterfall as I thought. Also, I notice that it was only happening on one extruder. Both extruders had the same settings, except the right (grey) extruder had Wipe set and the left (red) did not.