Imo they should completely seperate PVP from PVE meaning:
Target searching spells should be forbidden since there is no skill involved in shooting them and impossible to dodge
Gearwise it should be consider to ban usual gear from pvp and instead replace it with specialy designed pvp gear. This would make it much easier to balance the dmg and surviveabality of each player. I dont know how hard it is to implement something like this in the game but in my imagination it would something like the following:
-PvP is restricted to max lvl Players
-Once you reach lvl 60 you get your character duplicated but without any equipment and instead like a pvp starter gear
-To get better gear you have to do PvP and get a currency for winning ( like Arena Points in WoW)
This are my thoughts so far and i hope pvp wont be oneshotting and rather interesting 1 to 2 min fights.
I was thinking about it myself. It would probably be a DOTA style fight... fast, brutal, skill dependant and fun.
But in order to be so pre-set gears available to both players by choices would have to be a reality.
Also one other thing i think might be the solution is a change on how skills work in pvp.
Like Arcane bolt with seeker rune for example, in pve never misses, does regular dmg, etc.
In pvp it would probably have to change to doing less dmg, or reduced proc rate of crits or some other "nerf"
Like barbs Throw Weapon + Throw Corpse. That skill can deal up to 3-4 million dmg in an area in PvE... in pvp it would be a one shot most assuredly too.
PVP will be based on dmg reduction or items nerfs (only for pvp).
They have said many times that the game wont be never balanced for pvp.
Trust me... soon after pvp is out there will be changes to balancing it. Thinking blizzard will do anything else nomather what they have said in the past is just naive. All you can hope for is that it won't affect pve.