I agree It depends bon your tactics. But i disagree with your conclusions. If you want fulll scks to be offensive, you get someone like Trent who cant defend for shit (and is truly a midfielder) and your team is better for it. Same with his supposed replacement. Can you imagine a ball playing CB as shit as Trent was defensively actually still working?
Dumfries i consider a real fullback. And while he and his team have had a great Champions league run, he is just a good player. Average ball control, average technique, average crosser, average dribbler, above average defender and above average athleticism. Play him at sny other position and he is likely an average player.
Its hard to pinpoint the idea im trying to express. Perhaps its not even a legitimate idea. I personally found, full back to be the easiest position to play growing up. And when i coached youth football, it was the one position i could hide my weakest players to create the least damage.
It's also the position you could bring a young player into and find success. Lewis Skelly and O'Reilly being obvious examples of late.