Not at all a poor way of controlling boost pressure, there are still many people that use this method because its cheaper, simpler, accurate and responsive. The BOV's are modified with the use of much stiffer springs, some even utilise a twin BOV arrangement. The only downside is that those using air flow meters, may upset the AFR's if routing back into the inlet as the incoming air has already been accounted for. Some people have numerous trophies to back up this system, so it works well enough. But hey thats the world we live in where external wastegates are considered the best thing since sliced bread, when infact it couldn't be further from the truth