World PvP is an absolute yes for me, however I know too well that it can go badly as well. So let's think of a solution to make it the least abusable.
1) I think what Puffy said about limiting PvP activity to levels around you is a good mitigating tool. Another thing to think about is gear. Few patches down the line, a max lvl character will be significantly more powerful than a max level character at launch. So a lvl 49 character in leveling gear wouldn't stand a chance against a fully geared lvl 50 character after few raids/pvp seasons have rolled out even though they only differ by 1 level. So setting item level ranges might be something to think about as well.
2) You could simply disable pvp in the starting zones as well, that's where the potential for pvp abuse is the highest. For later zones, if you want a more organic pvp ecosystem, you can set up bounties for players that killed you, as you said in one of your early YT videos. As long as that bounty rewards a good amount of pvp currency/valuable reward, there will be players waiting for them to appear to farm said currency/item. I think this, maybe coupled with lvl ranges is the solution we may want.
3) Another, much more difficult solution would be level scaling. This of course changes the game fundamentally, but it alleviates the problem of level difference altogether.