For this update at least, PvP is restricted to the castle area. You can challenge people to a duel just about anywhere in there I think (as long as they accept) and the Arena located in the castle is more of a group oriented battleground, or simply a free-for-all. In time, I imagine they will add other zones that can be designated for PvP, or clan warfare, or special games like capture the flag/castle/etc. but I think they want to get the community to try it out on a smaller scale and get feedback before going forward with this.
PvP does not really interest me that much (unless it is good, friendly fun), but judging from the shout board lately there are plenty of people who would love to have at one another. With this update however, people will have to be willing and able to travel to the castle to settle their grudges... This being the case, the current format for PvP is basically a fun thing to do when bored, and only dangerous if you put yourself into the fray voluntarily.
Swearing is blocked from chat and this hasn't changed. People who try to circumvent this constantly by inserting spaces between blocked word should be advised that admin will have moderation tools at their disposal and will be able to mute you (or possibly worse) if you are out of line. If there is no admin online to take care of it, you can always block the person swearing and/or report them directly to support - no need to send screen shots, they can track everything that is said. Sailor mouthed players should also grow up and realize that there are children playing this game, but that isn't likely to happen... sigh (I also realize that many youngster are among the most foul-mouthed around, but I stand by my statement).
Not sure what you mean by "boss group?" or "ks?" but you won't be able to kill off people who are competing for frags if that is what you mean.

Once they work out any kinks and find out what the masses want to see in PvP though, it might be interesting to have certain PvP areas where fragment dropping bosses can spawn (occasionally) and people can have a battle royal over discs... (maybe drop the odd Falgren into the arena, just to mix things up once in a while

)
One thing I know for sure, I don't want to see entire zones getting turned into PvP areas, particularly where quest objective bosses normally spawn. Competition is stiff enough as it is, and PKers/Griefers will just make people sour.