Whole routines are ideal for natural trainers. Splits work too. In splits there are over laps of training bodyparts. You can't really isolate the body to well. Lets take a typical split. One day is chest and back. The next is legs and the last is delts/arms. When you train chest and back there is absolutely no way you can train them without training the tricep, bicep with some delt involvement. Doing deadlifts on chest and back day you are training legs. On delt and arm day lets say one of your tricep exercises are weighted dips or close grips. You are then training chest too. So split routines you are still hitting the other bodyparts.
Whole body routines are constantly given the beginner status but as I said previous I think it's way harder than split routines.