Clearly there are issues with the implementation of Co-Processors in HBase. Nevertheless, there is a need for server side functionality to enhance existing features. (E.g Security... type constraints, indexing ... )
Its possible to offer the ability to extend MapR in a more secure manner and thus offer a stronger product.
There are several ways that this could be implemented, and that would take a more detailed discussion, however its important to first agree that such a feature holds merit.