No GUI option to change size of orientation axes
It is possible through Python: https://public.kitware.com/pipermail/paraview/2017-April/039837.html But the axes from the Python solution does not show up in the object inspector, and cannot be dragged by mouse.
A GUI option for zooming will be quite useful. The default one is simply too small.
I also attempted to use the Axes filter. But that does not give arrows and labels.
A possible workaround is to get the handle to the vtkPVAxesWidget object in Python and change its ViewPort.