It could be my bad. Let me explain my experience so far.
I absolutely like the existing yEd stencils. I refer to them as "natively developed stencils/shapes". They look sharp, they have the connection points defined so the edges connect properly (not outside or somewhere inside the node), and they have a list of parameters that we can customise (like line width, line colour, etc.).
Some time ago I needed some symbols to add to a set of diagrams and I imported SVG pictures I downloaded from IconFinder. The edges were connecting in all crazy places, as no connection points were defined, and the end result was far from great. I also had to use the SVG images as they were - there was no option to change any parameters as most probably such were not defined.
I would like to add ArchiMate 3.1 and C4 stencil sets, and I would like them to look as neat as and have the functionality of the other stencil sets available in yEd. I don't know how to do it though without compromising quality.
I see that yEd live already has AWS and Cisco Network Topology stencils. Are they also available for yEd for desktop? If not, is it OK to export them from yEd live and import them to yEd for desktop (and how to do that)?