I'm going to assume you know about the characters and stages already announced which is mostly what the article talks about. "Ayano insists this isn't just a case of dropping a failed game's models into the engine of one whose appeal endures five years on from its arcade debut" [...] "The absence of SFXT's universal Boost combo system will certainly mean that four of USFIV's five new characters play differently but they sure do look the same" [...] "Until we see the curtain pulled back on USFIV's fifth pugilist it's tempting to see USFIV as Capcom at its most iterative."
Cammy and Akuma will be toned down while buffing up characters at the other end of the tier lists. They want it to be balanced while retaining diversity. (seems obvious to me)