Well you have to keep in mind when Sasuke said and did that, as he changed his goals many times. He could still want to kill Naruto or not.
Also ruling the world? That was never his goal and hasn't been stated.
I don't know, but as of right now I don't him being a final villain. Of course we have to see what his real goal is, so we can't really say much can we.
No what he said was "I'm going to be Hokage and I don't give a bleeep if you agree nor not. Don't get in my way." A tyrant is someone who will not allow people to speak against them or stand in their way. In order to change the shinobi system he has to take control of it which would pretty much put him in charge of the world as Ninja's know it.
What do you think he'll do to people who get in his way? Kill them obviously because that's the sort of person Sasuke has become.Usually when someone makes the declaration of "burning everyone and everything" without distinction, we don't consider them good guys, do we?
Just because he DIDN'T do it doesn't negate the fact that he was going to and that he WANTED to do it.
Sure, lets keep in mind that Sasuke is screwy in the head, easily manipulated, sociopathic, "changes" his mind on a dime ( really, it haven't changed at all, his goal is still vengeance the target and method is just different.) No matter how you want to call it he's not a GOOD guy.
A bad guy doesn't become a good guy just because he doesn't want the entire world ( and therefore his autonomy) to be destroyed. It just means he doesn't want his own interests to be impeded by it and therefore works to stop it. When the issue is solved he'll go right back to where he was before; trying to get rid of Naruto& co, because what point would there be in a Naruto VS Sasuke fight other wise?
Him standing in Naruto's way automatically makes him a villain. If you stand in the protagonists way it makes you the antagonist- I.E the villain.