Perhaps someone can produce the exact BioWare statements about the relationship between MP and SP. I remember one which stated that the development of MP did not affect the quality of the SP game (and in fact had helped in the development of SP, but unless we have precise details this discussion is likely to continue to go around in circles.
https://twitter.com/...368550979444737
Edit: also, one can make a case for the FAQ itself:
Do I get to transfer items from SP to MP? Or vice versa?
· In Dragon Age: Inquisition, you are in charge of the Inquisition, and in Dragon Age multiplayer, you control a few agents of the Inquisition. There is no connection between SP items and MP items on purpose. We wanted to make sure that the two economies are separate, which will allow a stronger progression in both SP and MP. If you play Dragon Age multiplayer, you will learn how each class plays a different role in combat, how different skills work, and how your party composition can give you a tactical advantage on the battlefield. This knowledge is transferable to SP, but items are not.