T7 is just sick. Having played King and Nina since 1, here are my thoughts on them...
King is better in high level play than he was. They slowed him down and decreased the amount if blockstun on his quick attacks, but they gave him many new tools for punishing opponents. He's no longer a poke machine. Now, he has ways to deal big damage beyond just comboing off his 2 and 3. He struggles more with pressure, but now has easier answers for anything as long as his user makes the right read.
Nina was always a poke machine, but she has improved in that categiry and she has lost nothing in her combo ability. In fact, she has become a more inclusive character because many of her strictest frame punishers have been loosened some that more players will be able to make use of her. They took what was good about Anna and created an Anna-Nina hybrid with the strengths of both of them - and it helped curb their weaknesses. This is definitely the strongest iteration of Nina or Anna in any Tekken ever.