sorry man but pretty much wrong... as long as you arent doing some dumb piece of shit volume routine from flex then you really wouldnt even come close to overtraining by doing that split. Once a week training is so unefficent its disgusting, people jus really dont seem to understand how important FREQUENCY is. Also, overtraining is not something that happens in a week due to excessive workouts.... its a process of continual cns fatigue over a given period of time. In terms of training to failure, i wont state my opinion, but its definetly not the only or the most efficient way to train. And no, you dont need to switch exercises each week to stimulate the muscle. The only way to get bigger is to get STRONGER.. and the only way to get stronger is by picking one heavy compound movement ie barbell bench press for chest... sticking to it for a while and making some sort of strength gains each week. If you are switching up ur godamn exercises every week like a madman, then you cant really specifically get stronger on any one exercise. The scientific concept of PROGREESIVE OVERLOAD right there in a nutshell for ya........