I can appreciate the technical issues with managing changes by factors outside the plugin. The problem for us is that the demos are often fairly trivial, so one tends to extrapolate behavior based upon the norms of the framework in use.
In Angular, there are very specific patterns at work, and so, lacking more complete examples using Angular behavior, one would reasonably assume that standard Angular patterns and practices will prevail. I would not expect to have to look to see if using a directive the way directives are intended to be used is "recommended" by Telerik, I would instead expect to find explicit warnings to the contrary if they exist, which is not something I've seen.
If that were made clear, we would have started out by wrapping Kendo controls in directives ourselves, but without knowing about these limitations, we acted based on good faith of expected behavior, and for the most part, the fact that these techniques worked quite well until the current release is reaffirming evidence.
Our "upgrade" is almost complete. It's cost a team of 5 about 6 days to correct in a fairly complicated Single Page Application with dozens of views and complex states/behaviors.
I think it would be beneficial to other clients for these limitations to be front and center in the documentation, as they are VERY large caveats in how one would naturally expect a directive to behave.
Future releases would be greatly benefited by details on changes to Angular binding behavior, we'd appreciate notes in the next release that affects them.