This seems to be more of a philosophical vision to change mankind's perception of the Earth rather than being a scientific theory. This is all about how we should perceive nature and our planet rather than what our planet really is. As a result I find it from a scientific point of view utterly redundant and useless, especially taking into consideration the contradictory nature. If you would follow that "theory" literally, well than whatever we do can never be considered a "mistake" as we are part of the organism and whatever we do is by default justified.
There's a reason why people are so obsessed these days with Mars. Because it's barely a few months away from the Earth, but it's a complete wasteland where scientists already get ecstatic when they find a few pools of water. If our planet had been just been a bit more to the right or left, everything could have been completely different. The Earth didn't decide to exist right in this place because it was convenient for life, the Earth coincidently ended up having all the conditions that enable it to have life. If one of those conditions disappears, it can kill all life just as easy.
This is pretty much the principle of Newton's Third Law, that every action has an equal and opposite reaction or something. When something happens, there will be consequences and these consequences follow the laws of nature. There have been five mass extinctions in the history of our planet. Putting aside the asteroid that wiped out the dinosaurs, which can be considered an external factor, most of the other extinctions happened due to the planet itself. Why? Because an action happened and the reaction was the extinction of nearly all life on earth. Nature does not "undo" or "restore" "mistakes". There will simply be automatic reactions that could both destroy as support life.
When you introduce a new species into an ecosystem and that species ruins the original ecosystem, only mankind would see it that way. In reality the ecosystem merely changed due to the conditions. That's why this theory is more philosophical/ideological than anything else. It gives the impression that there is some kind of an original natural order where everything works harmoniously and that we are screwing it up. It's the complete opposite of that, that's not how nature works. It's a chaotic, merciless world that will automatically destroy anything that will not adapt to the everlasting changes. For every species that exists today countless of others disappeared and I'm pretty sure none of them ever did something wrong to deserve such a fate. Nature consists out of an infinite amount of actions and corresponding reactions, from ones limited to your backyard to ones that cover the entire world.
It's a nice concept for people so that they would perceive the world differently and might act more respectable and responsible for our world, but from a scientific point of view it's bogus.