I personally expect them to have an entry-level 8 core cpu for their HEDT platform, maybe not initially. There were ones already wanting more PCI-Express than what AM4 provided. An 8 core with a Quad channel memory controller and 64 PCI-Express lanes (even more than Intel's new HEDT coming out IIRC) would be the sweet spot for more than a few. If yields are to good though, they may not make one.
I think they would. It would basically be free money. Cut back on some 1500/1400 stock ($130-$170 CPU's) Create a $550 CPU to slot in above the 1800x. Then a 12 core for $750 and a 16 core for $1k. There goal should be to get the ASP per Zeppelin die as high possible but not to price it out of the market for just another "AMD" purchase. Compared to the 6950 the 16 core would be a steal at $1.7k. But for but that is too much for a workstation or home user and is solely in the server territory for AMD purchases. These prices would increase the ASP, while keeping the cost in range, by being an "amazing value" this gen they kind of lock people into the platform. In 3 years if you had a HEDT setup from AMD would you switch to an Intel platform if you could still get a really good upgrade for your current motherboard. It's one thing at the $100-$200 it's another on the $250-$400 range for the boards.
This is where Intel's socket replacement cycle is going to bite them in the butt. Every upgrade for pretty much 98% of the people out there requires a new platform. There isn't any savings by staying with the manufacturer. If I could have just gotten a BW-E 8 core even at the $1k it costs now to throw into my previous system I would have done it in a heartbeat. But instead I was looking at a minimum of $1500 just to gut my machine for the update. That $1k while wildly expensive would have been worth it the extra $500 took it into the range of a full Ryzen 1700 build. Same thing will happen 3-4 years time. People will be looking at their CPU's and wonder if it's time to upgrade when they do, they could look at Intel and it will be certainly a CPU and Mobo purchase. With Zenver 3 or 4 it could still be a drop in replacement and even if AMD is selling at more of premium level it might still be worth it even if Intel still has a performance lead.
A little bit of tangent there but the main point is a 8c HEDT CPU is a good way to get people into a platform that people won't have to change if they don't want to for upgrades and selling them at Value pricing specially as they are trying to rebuild loyalty and good will would be a great way to get followup purchases.