The problem is not the world pvp. World pvp was there in vanilla too and we all liked it.
The problem is the incredible, massive faction imbalanced on many servers. Most servers have a faction imbalance of 20%-80% or even worse than that.
On a normal situation you could have more fair encounters and it would be enjoyable. Since yesterday, on my server, we managed to fend off an equal number of horde fairly easy, especially late at night. But on prime time, even if you wipe them 20v20 or 40v40, hell even 20v50, they just write a message to their world chat and in less than 5 minutes that zone has a 20v500 situation.
I’m not even exaggerating here. We managed to kill 2x or 3x more horde than our group had yesterday, and all we had was 10+ full raid groups of hordes in the entire zone.
And what does Blizzard, the most incompetent, indifferent and ignorant game developer on earth has done about this? Nothing. We knew this was coming and we made posts about this earlier. As always, Blizzard just ignores all suggestions, similar to what they did at launch with only 2 pvp servers in EU.
They will simply not give a damn about what you experience. They will sit there, enjoy their cigars at their corporate HQ while all servers will be one-faction servers like in retail, and eventually they will have to bring cross-realm zones to fix it later on.
So, enjoy classic while you still can.