There is a lot of discussion, arguments and suggestions relating to Primal Ancients and Blizzard has Ideas on making them more interesting as do I. As a 5 year member of Diablo Fans and lurking prior to that I've seen some awesome threads and some incredible photoshop skills come into play when a few people with a few good ideas come together and that's where the basis of my suggestions come from.
I personally like primal ancients, the idea of another step up, adding grinding on top of grinding and in my opinion that is Diablo but I also believe that they should be more than a % increases in number ranges and a few way to simply tweak them, add some flavor or spice to the items are listed below.
- Visual differences in-game i.e. different colored glowing effects, cosmetic variations of the normal Legendaries to add some eye candy. Not making these new appearances transmogrifiable (?) will give a way to show off or running into somebody with that Golden Wand of Woh or a Primal Tals set giving off an angelic aura will inspire you to set out on a new adventure to look as awesome as they do.
- Adding an extra primary or secondary attribute to the armor and weapons unique to primal ancients but not game-breaking OP abilities or stats. Some examples of this could be as simple as a permanent XP bonus or more exciting such as a randomly selected ability on primal weapons / armor such as the first attack on elites slows their movespeed by %15 for 2 seconds, killing an elite pack grants you %100 more gold, after being hit by a champion or elite ability they're stunned for 1 second, after reviving move through enemies unhindered for 1 second, after reviving nearby enemies are stunned for 1 second, elites and champions also drop 5 blood shards, elites and champions also drop bonus crafting materials, and many more to chose from specific to weapons or armor that can not be enchanted that also do not dramatically effect gameplay. Attributes such as stunning enemies would not stack but bonus mats and blood shards would adding some variation. Getting that well rolled primal would be exciting then to read "Awesome, elites drop some blood shards too!"
- Adding another layer of depth into these items may be difficult but an ability to "level up" primal ancients all on their own could be another cool aspect with minor rewards such as "per level primal ancients draw closer to perfect stats" if you got a really good primal ancient with the perfect attributes but terrible rolls the item would start at level 0. you can reroll one attribute through the mystic as per usual but the ability to level up the item as you play could but the rolls up ever-so-slightly towards perfect. In example I find a primal ancient balefire caster. Damage is good. Rolled everything I want but the dex is as low as possible. Usable, definitely. Now this item levels up very slowly, with every level it adds automatically adds to the dex. Lets say items can be leveled 100 times. 1 dex per level. Not game breaking and sure it adds more grind but unless you were perfectly geared you wouldn't specifically grind XP just to get 100 dex but using the item over time draws it closer to being perfect.
- Combining the two ideas of leveling Primal Ancients along-side the specific primal ancient attributes, at a certain level you could select the attribute you want for your Primal as it slowly and progressively levels with the item. For example, you've leveled your primal ancient to 10. I want more blood shards starting at 3 blood shards from every elite pack, every 30 levels on the item it adds 1 more shard for a total of 6 blood shards per pack killed stacking alongside other primal ancients. I believe minor things like this will add some fun and depth, nothing game changing, but something else fun to strive for.