Sorcs are probably borderline manageable if it's just one of them, but hardly a WZ goes by with only 1 healer now. Add another Sorc and now it's much harder to focus on them. Add an Operative and you can pretty much forget about trying to burst down either healer.
Of course since healers are all over the place it does indeed boil down to DPS but it's a rather degenerative form of gameplay. Your DPS isn't really beating the enemy healer if they're at all good, though this applies to your side as well. In the optimistic case this might mean your DPS managed to kill their healer twice which is one more than the amount of time your healer died, so this wins in the game. In the degenerate case this means your DPS was quicker at clicking on nodes as they're the best objective takers in a game where nobody dies (it's safe to do no DPS if nobody is dying anyway). It's likely the stronger team wins still but it's not in a way that's at all enjoyable. Objective based WZ simply doesn't make much sense when the total number of deaths on both side is in the single digits.
Well (imo) an optimal line up has 1-2 healers. 3 is manageable depending on zone, but if you dont cap first you may have an extremely rough time re-taking the node.
But healing is never going to win a match, at best healing will be a stalemate and even in a stalemate I believe that kills are the determining factor.
Which is why you are seeing a lot of new strategies to start wzs. You dont just simply send 1 person to node and the rest to fight at mid. You have some going 4/0/4, 2/2/4, etc etc, because getting the first tick matters. Having strategy matters.