Ummm, vinegar + oil is pretty much the composition of every dressing out there, sometimes with a small amount of emulsifier, such as mustard (vinaigrette) or egg yolk (mayonnaise). Is it the fact that you use olive oil that OS important? Or the fact that without an emulsifier the dressing is much thinner, and hence ends up on the plate, not the salad, so you eat less?
I just checked some random dressing in the fridge. It has 50% more carbs than fat. It has more sugar than fat. It tastes sweet. I should probably toss the piece of junk in the garbage, but then my wife would probably buy a replacement. :/