yes, the text-spliced shaders are annoying. Atleast in the webgpu backend, string-substitution is being replaced with slang shading language that allows polymorphism in shaders. The work is tracked at https://gitlab.kitware.com/vtk/vtk/-/work_items/19731. What are the problems with the mappers, MTime tracking and object model that affect PyVista? Yes, I understand, they get in your way sometimes as middleware developer, but that is generally not a great pain once you’ve built the right abstractions.
There are cases where even VTK produces incorrect results, and we’re improving them. For example: Say goodbye to lines bleeding through thin walls with polygon offset - #3 by michaelhogg.