I'm not sure what it is about these designs, but the first thing that jumped into my mind when I saw them was, "Jeez, Kingdom Hearts has really strayed far from that simple, innocent story about a boy journeying outside his island home."
My biggest concern is, just by looking at them and their outfits, they seem to be more style over substance. They look like a lot of those stock over-drawn characters you see in second-rate anime series. I'm trying real hard not to judge a book by its cover, but if the way the Union X characters have been developed is any indication, I don't have much faith that these new guys are going to be very interesting. And that's an enormous problem.
For all its many faults, people stuck through the long-winded Xehanort saga because the batch of characters that needed to be saved were all well-loved, and they all had stories that fleshed them out well enough that you wanted to see more of them. I haven't heard anybody express the same level of affection for Ephemer, Skuld, and Brain as for Roxas, Xion, and Axel, or Sora, Riku, and Kairi, or even Terra, Aqua, and Ventus. That signals to me how big a failure Union X is, and it makes me worried that Dark Road will fail in the same way. Looking at these character designs doesn't ameliorate those fears. You can name them any fancy old mythological names you want, but the symbolic meaning behind those names doesn't actually imbue them with any relatable personality. And considering how over-stylized they look and how...well...bland their designs look, I worry the next batch of people to be saved in this upcoming saga are not people that most players will actually be invested in saving. We need better than this. Right now, probably the only characters for whom I, at least, have any deep interest in seeing again is Yozora and those connected to him. The Union X cast just doesn't do it for me. And I worry these guys won't either, not unless Nomura can REALLY throw me off and present an amazing story for them.