So here's Frank Jackson himself responding to his own argument using "representationalism":
https://www.youtube.com/watch?v=YPT0BE1WAHk
So as I'm understanding Frank's newer view... when Mary "sees" red she's not learning anything new... what's happens according to Frank is that the brain is urging along knowledge about the physical world through experience/sensation... so it's a new way of absorbing old information.
Puzzled by this response. I mean it seems to me Mary at least learns what it is like to have this new type of brain experience she didn't have before. Even if the seeing of red is a "representation"... Mary still attains knowledge of that representation which she didn't have before. Am I missing something?