It is only faster based on its higher clock speed. I overclock my 4790Ks to a base of 4.4GHz so I am already exceeding 7700K speeds based on 2013 technology. Yes at a higher power draw but it doesn't really add up to much cost.
Yes but the later models can be clocked even higher. That's one of the benefits of a smaller lithography node - faster transistor switching times.