Of the remaining characters, Hwang's the one I'd least like to see as dlc (besides Rock but there's no chance of him happening at this point). I think it wouldn't be a great move for sales either, sure people here on a SC fansite know Hwang well but most people started with SCII or later, their only knowledge of Hwang is being one of many bonus characters in SCIII (I know he's a full character for AE but casual fans haven't played that). When they've got essentially 2 slots to choose from Hilde/Cassandra/Setsuka/Amy/Yun/Hwang/SCV's new styles, having one be Hwang would be a big waste. Yun would at least be recognisable.
Besides, Hwang's playstyle just isn't visually exciting. It's the kind of thing I can see them maybe doing as a quick made bonus CaS style, in case people want a generic swordsman style without having any strong personality come across from the original character. Yun's is more interesting to watch but in that case they're better off just including Yun.