Honestly the better solution is a 4 level system but also certain zones (maybe all of them, I didn't think this completely through), if you are below the minumum pvp range level for that area, you can be attacked.
This solves the Fansy the Famous Bard problem.
Zone A is PvP level 55 (higher end) if you are 55+, your 4 level range applies, if you are lower you can be killed.
Fansy zones in, lvl 5 with his train of sand giants. Nirgon the attentive 58 wizard in group sees the newb bard coming and roots him, train flattens him, the end.
RobXIII the lvl 80 Shadow Knight comes through and tries to cast on Nirgon, but he is protected as he is not within 4 levels.
^ Can teams of people really not think of working ideas like this to solve simple problems and design a fun/fair system?
Of course the people who can't compete in pvp against their level are going to go grief newbies for an ego boost.
I'm pretty sure if, honestly, they came to me and said devise a PvP system that is fun, captures that classic feel and isn't prone to griefing players exploiting it.. I could do just that.