Modular Rigging System : Goals

As I have started writing my modular rigging system, I am constantly thinking about the main goals. I feel that at each stage as I put a concept on paper or write code that should satisfy the main goals. After a lot of thinking I have decided on the following goals,

1. One should be to be able to change/extend pretty much everything in the system
2. All the parts of the system should be as much independent as possible
3. Whenever possible not be specific to Maya 
4. Editable template/skeleton/rig at any stage

So any module that I create can be changed or replaced. This will create very minimal core modules. We are not really defining the logic of rigging in the core modules. I think the core modules define the concept of modular rigging. And the modules that has some common logic for rigging are defined in core utility modules. Hence the core system modules represent only the idea of the modular rigging system.

Rigging modules should not be constrained to a personal workflow.
Example:
In general, there is a template system that lets us define blueprint of the rig and then we create joints and rig on top of it. So roughly there are three parts to this system, locators(guides), joints(skeleton), rig(controls). But,
what if I already have my joint chains created manually? What if I have my own guide system? or I want to change the way animation controls are aligned or created? etc...

There is really no right or wrong way to do things here. But I am doing my planning based on what I think a modular system should be.