Weird scaling esp at maximum level makes it virtually impossible to draw a line.A level 90 killing a level 1 is probably overkill, but changing the system to anything else just begs the question of where you draw the line. Like I asked before, is 1 level difference too much? 5, 10, 15...? Or if someone of equal level kills you repeatedly for hours because they have arena gear, do you then have to add in item level restrictions as well?
No matter where you draw it, you would essentially just exchange the victims for another group.
EG: make "grey" level players unattackable -> green level players become the target of choice and the whine continues.
So basically it's just one thing you can do and tell others to do:
READ THE F***** MANUAL before creating a character. I think Blizzard gives ample of warnings and information about PvP realms on their website. Maybe they should implement a warning screen in the game as well, informing non website readers about what they sign up for. Make it so it only appears for the first character of an account that is created on a PvP realm.