I kinda wish they kept the KOF XII voices.
WHAT DA HECK HAPPENED TO JOO?! Robert's voiceactor is at his best in this game.
To be honest, I never had liked the English Voices in KOF XII.
And like most of you guys said, it wasn't needed before, but it is needed this time because like how DarKaoZ mentioned, this is the first time SNK is doing a Story Mode for a canonical KOF game. Besides, I can't even understand what Saiki and Evil Ash are saying if the game were to have Japanese voices only, and there are going to be no subtitles during matches, so I find subs to be useless for the in-game experience.
Anyway, observation time!
My newest observation is that since Johnny Yong Bosch, Cristina Vee, Cassandra Morris, Tony Oliver, Patrick Seitz, and Stephanie Sheh (Just to name a few) are guests at Otakon this year, I think this might hint at something related to the game or not... (Hints that the game might get a new English Dub after all? or, are they there just for fun?; I suggested them for Kyo, Athena, Kula, Takuma, Ralf, and Rose, respectively)
My new observation is just a theory/guess, so this is nothing official or whatever.