Yep, most low-end (?) units are those goblin/hobgoblin slaves. And wolf riders.
What is there at the high end for Chaos Dwarfs? Certainly the bull centaur should go there as a knight unit. Then there is also the great taurus (a flying unit) and blunderbuss (superb defender?).
I think that the bull centaur would be a great unit (and very much appreciated), and I would do it, if I had the confidence

- well, it really doesn't hurt to atleast try
And what about those already done?
- whirlwind war machine? What the heck should that be? A cavalry unit? A bombarding unit? A fast defending unit?
- earthshaker seems to be a high-end bombard
- lava elemental? a foot unit available at the-tech-that-allows-the-earth-elemental-tower-wonder (see how good my memory is

)
- hero is an infantry (or a troll/dragonslayer-level unit?) and king
- sorcerer is a sorcerer (duh)
- the upcoming chaos-dwarf warrior by kinboat could be infantry-level unit