thick lats make your back thick...pulldowns build lats, pulldowns make your back thick!
SImpel as that. Every muscle in your back will create thickness!
All people i know having weak back mostly do heavy rowing excercises...I think all form of pulldowns will give a much greater backdevelopment bcz of the full movement stretch all the way and the contract... And lots of lots of set for the upper back/rear delt. Then some stiffed deadlift normal deadlift and seatet rows with full stretch...
I think dorian motivated a lot of people doing standing barbell rows that excersise just look and feel like shit, no movement whatsoever, and 99% of folks like to put on more weight they can handle and just meet the bar with the chest...witch actually mean no back development what so ever...