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I may be mistaken but i havent recently found any discussions for the new WOC book on the Dragon. Would this not be a viable choice? I hear all this talking about we have no flyiers, and i think with a cav based list he could be quite powerfull IE have you seen his stats? he could really rack up some CR.
Because of the Cost of a Lord character and the cost of a dragon, its quite a big point sink into 1 model.
Granted it could do alot of damage if tooled right but I think the points cost is too much.
Dont forget you can take a manticore aswell, which is a bit cheaper then the dragon but is still a flying terror causer, and with a chaos lord on it, it will still be pretty killy but will be a bit cheaper then the dragon, though not by much.