I made the erroneous assumption given you were at least aware of the basic ideas of scripting. I will admit I am not a great scripter, though I do find it fun since the interface for Arctic is so easy. Here is my basic approaches to your "high level pk" scenarios, each of which is the exact action a human player would take.
Basher on scripts: sets pk target with bash triggers... Now what if that person is also hasted and stands and flees.
A 3rd grade level script would have a list of targets. If the highest target on the list is not in the room (i.e. dead, recalled, fled) then you move to the next target. A 5th grade level script would resume bashing that target if they returned to the room. The same exact action a human player would take.
What if that person is a healer who took the white robes hardbash or nobash items and you're just sitting their missing bashes being completely useless.
The 3rd grade approach to this is if you miss 2 or 3 bashes in a row, have the script move to the next target in your list. The same exact action a human player would take.
What if your target is a black robe and fluke made you bash your own healer.
The 3rd grade approach to this is the same as missing bashes... if you are attempting to bash a target and they aren't landing on that target you move to the next target. The same exact approach a human player would take.
What if the enemy brought an unknown healer who is just free casting but your group doesnt have anybody to bash him bc everybody is scripted?
Wow! Great point. Why don't you have a script that makes the highest priority bash target in the room any player casting heal that isn't in your group. While you are at it, you could even have it auto-prioritize other high impact spells like PWS or nightmare. The same exact action a human would take.
what if a paladin is guarding your bash target?
At risk of sounding like a broken record, the simplest way to account for that is if you try to bash a target and fail (or hit something different) a few times in a row then change to your next highest level target. Now, since we are talking "high level pk" and not low level pk or even mid level pk, if you wanted to be really elite, I suppose it wouldn't be too hard to parse the text for the various protection type skills/spells so you corrected the problem first go around. The same thing a human player would do.
these are just a few examples that I came up with in 1 min of scenarios I have seen in this game.
If this is the pinnacle of "high level pk", I think you proved my point. The character control and decision tree that goes behind it is simple. You are right in that reading through a wall of text can be difficult though... if that is your definition of skill, you win.
Its 8v8 (used to be 10v10 and 12v12) chess
I think you may be being blinded by your greatness at Arctic. Since you brought up chess and most people would consider it one of the purest games of skill (which is obviously only because most people haven't heard of "high level pk" in Arctic), maybe it would be more instructive to do a comparison. I just described scripts that are trivial to come up with that play the game equivalent to a human. If "high level PK" is like 8v8 chess, take a stab at describing the decision tree behind a fairly simple end-game chess board. I have a King at F7. You have your King at D3, a Bishop at G4, and a Pawn at H2. Describe how to checkmate me...