I think the reason for the drain back has nothing to do with efficiency/effectiveness of the catch can. It's simply so that the catch can does not need to be emptied. This is "OEM style" because the average person buying a new car doesn't want to deal with emptying oil catch cans in addition to oil changes. It would be a nifty setup if you had an easy/convenient place to run the drain hose to, but probably not worthwhile if it requires significant modifications to make it work.

Also the drain back feature on this would be completely different than simply mounting a standard catch can up high. The high mounting position will only cause oil in the hose that didn't yet make it to the can to drain back into the engine. The special drain back can allows all captured oil in the can to immediately drain back into the engine, minimizing overall oil level loss over time.