Blender has Python API for users to develop add-on.
I think, this is one of the powerful features in blender.
However, blender has no Python API for developing modifier, because Python script is slow and unsuitable for modifier.
So, how about loading custom modifiers dynamically (written C/C++) instead of Python API.
For example, developer made own dynamic library. (.dll for win, .so for linux)
Then, users download it and install.
I did not know this feature already discussed.
This feature will blender more powerful
What do you think?