I built my desktop 14 months ago at this point with dual 970s, an i7 5820, 32 gig of DDR4 3000 ram, and a second gen M.2 SSD. it is more than twice the stats of my laptop (other than cpu) and my laptop was capable of running 12 instances without issue. I am the first person to load in every dota 2 match typically in under a couple seconds, where as the laptop often took 30 seconds or more. My guess is it is because the M.2 drive is stupid fast. The same thing happened when i played EQ, the SSD created stupid fast load/zone times and was a bottleneck that I hadnt thought about previously. Now my bottle neck is my router (that I plan on upgrading today).
So my biggest suggestion is make sure to have the latest gen 3 or 4 or 5 M.2 SSD for max speeds. Then worry about RAM (because with everything turned on it was eating 1 gig of RAM per EQ instance, so 64 is much better than 32 if you are thinking over 15 instances), then focus on cores, because more is more. For graphics, a 1080 is most likely fine, but.. dual cards bro!