One fact that we must all comprehend and learn to accept is that the headphones are simply the last link in a long chain. When we say that something sounds "neutral", what do we base that on? Were any of us in the recording booth or live setting when the sound was captured, or do we base it on how natural it sounds based on the sounds we've been exposed to throughout our lives? The fact of the matter is that, when we judge whether something sounds neutral or not, are we not entirely basing that on the assumption that the original sound was recorded perfectly and all other processes between the recording and final playback have also been done absolutely perfectly?
Let's say that everything has been done perfectly, wouldn't a set of headphones that measure neutral in fact be the most detailed set of cans? Surely, it's impossible for something to sound more detailed than what it sounds like naturally (after all, isn't it that realism that we're trying to capture and playback?). In this case any set of headphones that don't sound neutral would, by definition, be distorting the sound and thus be less detailed.