I maintain it makes zero sense that Nero plots to destroy Earth and the Federation because the friendly Vulcan that went out of his way to help Romulus arrived a bit too late.
Just another bland Khan clone. Hopefully Cumberbatch is a better Khan clone. He definitely seems to be giving a much better performance than whatever Bana was doing last time.
I think it was pretty well established that Nero was batshiat insane, so trying to apply logic to his actions is not going to be fruitful. As for the actor's performance, thats up to individual taste.
Bingo. I think the actor did fine for what it was: A rage filled, erratic, nut case out just to hurt people. There was no revenge, no justice, no evil, it was just pure on rage, hate, and I'm going to make you hurt like I'm hurt. It was animal, to use a term.
As for the logic of nuking Earth/The Federation. About a logical as the Borg Queen going after Earth or Shinzon going after the Earth. Or: It's Star Trek, out of millions of worlds, Earth and humanity are special little snowflakes that everyone likes to pick on.