The first example @lassoan gave was a convenience API to set two properties at once (XResolution and YResolution).
I also see no reason to remove this convenience API.
Having convenience API that sets multiple properties at once is a pretty common thing. E.g. I can think of examples in Qt API where you can set left/right/top/bottom margins individually or all at the same time.
If we forget what is “non-VTK” for a while and think of what you want VTK to be, what is so inherently bad with this API that you want to break applications?
We also don’t upgrade VTK at every or even every second minor version in our project. We are still at 8.2 and planning to move to 9.x some time next year, if time permits.