I am aware of one of the big gripes that players have with D3, and that being the lack of customization in builds. At least from an end game stand point, Sets dominate the scene and are typically the only viable options to do Greater Rifts.
Legacy of Nightmares (LoN) is a great step forward to making custom builds again, but even so, only a couple are really only viable. If we are to look at the end game of D3 being GR pushing then all LoN builds don't cut it, save for 2-3 of them.
Now we have Primal Ancients.
I am attempting to find some math in regards to the stat increase from Ancient to Primal Ancient. If the secondary stats like Vitality, Strength/Dexterity/Intelligence, Armor and the like are much higher than the regular Ancient rolls, would that be a significant enough increase to ensure damage output and survivability in high GR's?
(1.) I first read on the official D3 forums that the increase from Ancient to Primal Ancient is around 16%. That would make it about 30% over regular, so from regular to Primal Ancient would be around 46%. Of course, I found no source to these numbers, so this could all be wrong.
(2.) Also on the official forums somebody linked this formula: 1.16 x 1.3 = 1.508. Again I am unsure of the source here, or even the context of this. Would the 1.16 represent the original, and the 1.508 being the increased outcome?
(3.) The rate at which Primal Ancients drop/reforged seems to be around 1%. Between the official D3 forums, diablofans.com, and icyveins.com the consensus many people are coming to is that it is easier to reforge Legendary items in Kanai's Cube. The amount of materials needed aside, the percent seems to between 0.5% - 1% chance still. If you are lucky, you'd be able to get a full set of Primal Ancient gear, with Legacy of Nightmare rings, in "no" time...