I think you're falling into a trap that's easy to fall into, and perhaps lies at the crux of the criticisms leveled against Peterson. What I'm about to say has certainly been more eloquently stated by someone else, but I'll do my best here. As I see it there are effectively two types of knowledge acquisition and transference. The first is explanatory knowledge. Scientists and philosophers work to build new explanations of the world. In this realm, it makes no sense to re-tread familiar territory, and the faster we accumulate this knowledge, the better.

There's another realm, and it's what I would call cultural knowledge. These are like "social truths" that are arrived at via some method of consensus in a given group of people. In this realm, the re-treading of familiar territory is acceptable, so long as the knowledge still needs to propagate throughout society or be contested by those who deviate from it. In this realm faster is not better, because these truths act as societal stabilizers.

I see Peterson's influence as belonging to the second realm. I find it irritating when people point out that "it's been said before". Yes, I'm sure it's been said before, but that is not the point. The point is to revivify that knowledge within a culture. To assume he needs to tread new ground is to treat him as belonging to the first realm, and I don't think that's the correct approach here.