Look i didn't make this program. This program is created by older and expirianced lifters. And they said that this programs is really good for shoulders (main) and other parts. I don't think that my back will not develop. Ok maybe not like shoulders but i think that whole back is worked out. With iso lateral machine we already work the trapezius and upper lats and with front lat pulldowns we more work for lower part of the back and for wide form. I don't know maybe i will start with full body i dont know.
There is nothing wrong with a push/pull/legs split. It's an easy template to program from and follow. The problems arise when you throw the entire kitchen sink into the program without concern for balance and without foresight. Poke around the boards and you will see a number of people who describe issues developing their pecs and/or have shoulder problems due to scapula protraction and constant upward rotation (i.e.: forward shoulders) due to poor programming and this over focusing on the anterior muscles throughout their lifting career.
Keep it simple: for every
chest press you need a row
over head press a pull up
chest fly a facepull
forward shoulder raise a rear delt exercise
Next, stick to the basics.
Push 1: Focus on overhead press and assistance muscles
Pull 1: Focus on pull ups and lower traps
Leg 1: Squat and lunges
Push 2: Bench press + assistance muscles
Pull 2: Bent over row + upper traps
Leg 2: Deadlift and hamstrings