Sharp broadheads, and two holes (with one of them being on the bottom of the deer) will definitely help with blood letting.
But blood trails begin and end with hitting high pressure, large diameter piping. If you don't sever major plumbing, you're not getting a great blood trail.
Having said that - you can hit a major vessel, but the openings in the skin can be plugged by the muscle, fat, and other tissue that moved underneath the skin prior to, during, and after the shot. Deer skin moves a lot because they're so flexible.
Essentially, the things that cause and don't cause good blood trails are out of your control, really.
Two schools of thought make sense to me:
Because you can't make good blood trails, aim for center of lungs. Best odds of deer going down within 200 yards.
Because the only thing that makes good blood trails are cleanly severed major vessels, aim for top of heart/slightly forward of where most people do. You might hit a shoulder, but if you make it through, you're 100% cutting the pump station.
Brings to mind buck I shot last year. Quarter away slightly. I hit him right behind front shoulder, and exited in front of off shoulder. High. He ran 30 yards and flipped over. Blood sprayed out of both holes like a garden hose. I missed heart, and one lung completely. But I put a 1.5" razor sharp cut on contact head through almost all of the major plumbing. Blood pressure dropped to zero in about 3 seconds. Not the exact shot I'd prefer. But I do tire of folks who say if you're hitting a shoulder, you're missing. Deer die from lack of oxygen to the brain. If you stop blood flow to the brain they can't get oxygen. Cutting the pipe in half that sends the blood to the brain will stop blood flow.