I've become grumpy in my old age and so, whether justified or not, feel the need to spurt out this sort of stuff:
I'm not sure that simply slapping on additional 'Efficiency' cores is really sustainable in the long-run - at least not for a consumer oriented CPU. As far as I can tell, they seem to exist mostly so that Intel can claim victories (or parity) in multi-threaded benchmarks, because what workload is the typical consumer going to be running that involves using that many cores in the first place?
Obviously a lot of heavily threaded tasks don't need all the cache and features that a full core comes with, but many do and at that point I daresay that anyone serious about such work is going to be looking higher up the products stacks at things like Threadripper and whatever Intel comes out with because a 'proper' core is likely more important.
For balance, I think that 16 core CPUs by AMD are totally pointless for general consumer tasks (including gaming) too, but obviously many people buying them engage in hefty doses of confirmation bias in order to justify their overspend. We see that with GPUs too.