Disclaimer: I use English only when I read, so probably my post will be full of errors. I stopped learning years ago.
Desktop zooming is a killer feature introduced in Xfce 4.12.
I am a PHP developer, not desktop app programmer so I don't have a clue if my suggestion make sense
from technical point of view.
Is there a way to increase the resolution of the enlarged part of the screen?
What if, during zooming, the desktop would be rendered "on backstage" at high resolution (higher than set by user/system) in order to show the magnified area in higher resolution?
Is this possible?
Will it require a lot of resources?