In the recent live letter it says

It will not be possible to use advanced materia melding for STR, DEX, VIT, INT, MND, and PIE. You will be able to meld these stats into available materia slots.

Players may think this will lower the demand for materia; however, the scope on which materia can be melded for individual equipment will increase.
Has there enywhere been a statement of what this scope is (new materiatypes, more forbidden slots, easier melding)? I'm german and in the german translation it almost sounds like they want to introduce new types of materia. This would be really amazing.