There might be other ways around that in the meantime. A few years ago, this gem was presented at the Blender conference-- fast forward to ~12:16. The artist in this video created an interactive cloth simulator entirely in Python!
Unfortunately, he doesn’t share any details about the code, except that he ised Numpy to accelerate it.
Python does have raycasting features. Raycast is a method of the Scene object: https://docs.blender.org/api/current/bpy.types.Scene.html#bpy.types.Scene
Without doing some research, I can’t tell you how to find the matrix of the current viewport. In a pinch, you can lock camera to view and use the camera’s matrix.