the USB 3 would have been a manufacturer add on, not part of the chipset.
AMD CPUs only started supporting PCIe 3.0 with Ryzen. Previous to that it was only PCIe 2.0 as far as I am aware… I am not coming down on AMD CPUs, just telling my reasons for feeling that the x3709 and B350 boards feel dated. z77 was a good chipset
I think you have just become used to look at high end Z170 and Z270 boards. The Crosshair was a day one board, the Taichi, the Aorus whatever they called the top dog… there are already some really nice boards available and the new ones are on the same level as their Z270 counterparts, at least.
OK, TB and optane are intel exclusive as far as I know. And to be honest both technologies are kind of pointless in their Z270 implementation. VRM design is fine on higher end boards and subpar on the cheap ones. No difference to the Intel side. And ports… well they have those, what is your point?
Where? I don’t see it?
You seem to be missing the point. Z170 and z270 are the competition to which they are being compared. I am not saying that the AMD boards are trash or faulty, some like the taichi are good boards, just trailing behind in the latest cutting edge technology. I also understand that AMD does not have the same levels of R&D budget as intel as well but to a consumer, that doesnt really matter when they are spending their hard earned $
Optane is the Intel brand name of a joint Intel/Micron development. Micron have the opportunity to sell their own range of products that have stemmed from that development. There is no reason why, for example, AMD could not have incorporated the Micron branded equivalent.
Likewise, thunderbolt is just a mechanism to extend the PCIe bus outside the case while wrapping it in a proprietary wrapper. There is actually a standard for external pcie that is not thunderbolt. USB-C is open and just an electrical connector that is already supporting x4PCIe traffic wrapped in thunderbolt 3 protocol.
There is no reason why they could not have included an external pcie connector, even through USB-c if they wanted to. There is no need to encapsulate the pcie traffic in a wrapper. They already support ECC memory, setting up 32GB/s communications backplanes that can be daisy chained between ryzen, threadripper and epyc machines has just taken the entire bottom half of the supercomputer market for the cost of a few connectors given that threadripper and epyc at least has solved the problem of having more pcie than most people need problem.
eGPU for laptops becomes trivial, imagine an affordable rx 570 gaming laptop playing games running in crossfire with an enclosure that only costs $100.
Affordable 8GB/s external storage enclosures anyone? You can potentially do all that with thunderbolt now provided you are happy with the intel tax. It seems that the market is not overly interested in doing that though.
All that happens and it kills thunderbolt pretty much immediately. Zen is already engineered to split off pcie lanes down to the x1 level so implementing and creating a brand for it would not be that difficult for AMD to achieve. external pcie adapter cards for non amd PCs would be fairly easy to produce as well if you wanted to really open up the market.
As it stands now, other than the Zen based chips, there is nothing except nvme on AMD motherboards that was not available on a z97 motherboard from 2014. If you exclude the two usb 3.1 gen2 ports, Then it dates back to z77.
Optane as a disk cache, IMO will be as successful as IRST SSD caching was but where I do see potential with that type of technology is to turn it around and make the tech into a multi gigabyte L4 cache for CPUs using a DIMM form factor instead of an M.2 slot
Aside from the fact that even theoretically TB3 tops out at 5GB/s, those use cases are just not interesting on a desktop mobo. TB3 or any form of external PCIe could be great on mobile devices. But as long as we are talking desktop mobos you just put your drives and GPUs into the damn computer. If you want to deal with external everything … hey, you could buy a trashcan mac. 
We already have a multi gigabyte L4 cache, it’s called RAM. Optane (or the micron whatever) tech is amazing, no doubt. But let’s not make it a bigger thing than it is. Optane is for drives, like current NAND tech. And we don’t need any special implementation for that.