In my opinion most commonly used inverted role is missing currently. Inverted Fullback with support duty. For example if you look at City's 4231 morphing into 3241 wide defenders will provide width and overlap or underlap. Inverted Wingback on support operates too far up in midfield and Inverted Fullback is too conservative. Having four defend duties is would turn out toothless if trying to replicate City's positional play. Actually Wide Centreback on support seems perfect role/duty combination. I don't see any reason why it shouldn't be added to fullback role selection.
Another thing I don't think I've ever seen anyone playing as Inverted Wingbacks with attack duty play in FM. A fullback who becomes attacking midfielder, I don't know.
What do you guys think?