Not even BMW thinks the design is fine anymore, hence the design changes to the OEM CCV parts in later years and the fact that such systems were ditched after the M54 in favor of something more reliable.

The stock CCV design is horrible. Any system that can fail out of nowhere to the point of hydrolocking your engine with oil, yet is placed in such an inconvenient location as to prevent it from really being routine maintenance, is awful. It's too complicated of a system for such a simple, necessary function. I would have rather had a catch can to empty during oil changes than deal with this craptastic CCV system.

The problem is compounded by how often the M54 thermostat silently fails in the open position, preventing the engine from ever really reaching operating temperature.