As one of the developers that at least contributes to yEd Live (our in-browser equivalent; yEd is based on our Java library which I'm not working on), thank you :-)
That being said, as a UX guy I always love to look at competitors and find ways how editing can be improved or streamlined (and yEd has many features already, so some parts of it can be more complicated than I'd like).
I looked at yEd, and dropped it because it doesn't seem to support rotating shapes. I was quite surprised, since that is a fundamental feature of most drawing applications.
yEd is actually not really a drawing application, as you cannot (easily) draw generic drawings. What you see and edit is always a graph, consisting of nodes and edges.
For yEd the lack of rotating shapes is a deliberate decision based on implementation difficulty (it's based on an older yFiles library version), workarounds are available (importing arbitrary shapes), and the fact that in a graph drawing application there are several things that don't play well with rotated nodes, such as automatic layout and ports. For yEd Live we are considering to add the feature, but we're still trying to figure out how to lessen the impact where things don't work well together. After all, automatic layout is one of our main selling points. We have already implemented rotatable nodes as a demo [1], so simply adding that to yEd Live would be trivial from a technical standpoint, but we like to care about UX as well.
Other applications may not have the same constraints (graph vs. generic drawing) or may disregard some of the problems (e.g. in draw.io you get overlapping shapes when you arrange a diagram with rotated nodes, since for the arrange feature all nodes are apparently axis-aligned and not rotated).
That being said, as a UX guy I always love to look at competitors and find ways how editing can be improved or streamlined (and yEd has many features already, so some parts of it can be more complicated than I'd like).