length of workout doesn't matter much if your workout is intense to the point were you can't move afterwards
I like a balance between volume and intensity...which takes more time. Not every set needs to be intense to get benefits....or do you consider only intense sets to be beneficial?
I can fatigue any muscle in a very short time with intense supersets using light weights and using pre-exhaustion. 5 - 10 minutes would be enough on most muscle groups. Should I make the muscle fatugued in a very short time and get out of the gym then? I'd finish off the body so quickly I wouldn't need to come back the same day.