Of course not, because they have none of their abilities. Replace the DKs unholy theme with a holy one, and the DK will overlap completely with the Paladin class. What makes them so different? Their abilities, which is the same case with my Crypt Lord concept.
And Druids will never get the abilities of Elereth Renferal, The Crypt Lord, or Empress Shak'Zara.Paladins wouldn't ever use Unholy magic, so a DK doesn't overlap.
Which means nothing if they don't have the abilities. My money is on them never getting such forms because the Druid's abilities simply don't line up thematically.Would a Druid plausibly use Insect forms and turn into Spiders or insects? Yes they would. There isn't a case where multiple Druids with Tank specs would be necessary when a mere cosmetic would satisfy that fantasy.
The difference is that there was never a large number of Dark Ranger abilities that simply didn't fit the Hunter class. Even the Dark Ranger NPCs were essentially using Hunter abilities with Wailing Arrow or a random shadow ability. Blizzard further muddied the waters when they made Nathanos a Dark Ranger when he was the Forsaken Hunter trainer, and they placed Dark Rangers in the Hunter class hall.Much in the way a Dark Ranger could be a dark version of a Hunter Class, but I'm sure you would see how that isn't necessary. A cosmetic option satisfies that fine even without the majority of Dark Ranger abilities available. Same as a Druid missing a majority of any Crypt Lord abilities isn't gonna greatly change the core gameplay of a Creature-based Tank.
I didn't see any Crypt Lords in the Dreamgrove.