There may be a handful of X470 reviews I may do even after X570 launches for that reason. While I think X570 is going to be good, I think its ahead of its time in terms of bandwidth. We just don't need PCIe 4.0 for most things right now. Its great if your going to use the same number of lanes for an interconnect such as the bridge between the PCH and the CPU, or for devices that use less lanes as it gives them more bandwidth. Even AMD admitted that X470 will perform the same. I think it comes down to what your buying habits are. If you are going to keep that motherboard for 5 years, then you might want to spend more now. If you upgrade more frequently, I see no reason to go with X570 early on. At least, not on paper.
Where things will get interesting is when we start comparing X470 vs. X570 in two important ways. Memory speeds and processor overclocking. Are X470 motherboards up to overclocking a Ryzen 3950X? I bet most aren't. How does Ryzen 3000 series chips perform with memory clocked at DDR4 3200MHz vs. 3733MHz and beyond? Another thing I'm curious about is whether or not we can get better clocks or higher RAM speeds out of using existing Ryzen 2000 series chips on X570. My guess is no, but I can't say for sure.
While PCIe 4.0 sounds like the big seller, I don't think that's the reason to buy X570 anytime soon. If there is any reason to do it, I think it comes down to memory performance. Another possible impact X570 has is its flexibility for lane configurations. What motherboard manufacturers do with that is going to be another matter. We could see more variation in X570 motherboards from the manufacturers. They might all do the same things they've always done with X470. They might end up being virtually the same outside of VRM implementations and fluff features. We'll have to wait and see.
I may very well revisit the MSI X470 Gaming Pro with Ryzen 3000 when I get my hands on one.