I agree with most of your post, but this part is ... just wrong. WoW Druids have to spec and gear toward a particular role to be effective at it, and while they technically can cover other roles than the one they built for, they're going to be utter trash at it. Khelds, in their present state, are the same only without the option to buff one role up to that "good" level. Dwarf and Nova forms are flatly inferior Brutes and Blasters respectively, and the only reason human form can keep up with Sents is that Sents are themselves underpowered.
Druids (and hybrid classes in general) were originally built on the Jack-of-all-trades, master-of-none philosophy, and what happened? Nobody brought a hybrid to dungeons or raids. Because you were gimping the team by showing up with a moonkin when you could be running a mage. Blizzard eventually figured that out and granted hybrid classes the ability to be effective in their chosen roles.