The second article starts out well before it descends into madness.
Besides what Joe said (and there is not need to reiterate or add to that) what we have here is the assumption that strength training is finding one thing and having that one thing allow you to lift heavy while somehow having a certain amount of volume. The emphasis here is really bodybuilding and it's really lip service to strength.
I swear I am really tired of people mentioning the nervous system and things like "neural fatigue" or being draining on the nervous system like the first article. So damned silly. It's like saying a hot air balloon may lose heat "theoretically". Well, can you tell when a hot air balloon is losing heat? Yes, it starts falling out of the sky. It is something you can observe and react to. These days any time someone thinks they are talking about lifting heavy they have to go into the damned nervous system fatigue BS. Well, can you observe your nervous system being drained? Or are you just "theorizing" and basing your training on the theory that something in your nervous system is being drained? What is being drained? Do you even know? And if it is being drained, how do you measure that, observe it, and react to it? The answer is you cannot observe it, measure it, or react to it very well if at all.
It's always strength training with this kind of scientizing. We were talking about Lance Armstrong before. You're never going to see someone like him going, "don't pedal too fast too often or you might drain your nervous system". Um..what?
Base training on performance.
Going on about the importance of how heavy the first set is in a moderate volume multi-set setting leads me to think one thing: This person has never really lifted heavy so "heavy" should be taken with a grain of salt. People who actually strength train for maximal strength, and so at least ocassionally lift with near maximal weights, would not find significance in the fact that the first set of a multi-set workout is "as heavy as possible".
First, they would always lift as heavy as possible in the first set. Analysing this is like thinking that the only other alternative is ascending or stepped sets. So like Joe said "what is the alternative?"
So what are the assumptions here? Do you progress differently by lightening the other sets after the first? Does lightening those sets mean that you will be able to add more weight or more reps on the first set of the next workout? Intuitively, does that make sense? Or it is simply an assumption that the only set that counts is the first set and the others are thrown in for good measure because of considerations of TUT or volume? Meaning that of course, if you stayed as heavy as possible it would be too much and you'd fall apart. All these assumptions are simply assumptions and none of them hold water when training based on performance.
What you will find with at least 85% of webernet strength training information is that lifting heavy too much will turn most trainees into piles of jelly. It's always Lift heavy, but not too heavy and not too much or too often!
But what you'll see is that the median intensity is very low from a strength training perspective. Your body reacts and adapts to the total stimulus. Not just one "special" set. So, look at the workouts given and analyze what you think the intensity really is based on the whole workout and you'll have your answer. Do a search here for the term "median intensity" as well because I have discussed this in several different places.