I like that every single sentence in your text is based on your hearing only... FR graph of LCD-2 is for sure more neutral across the bass and mids than of both LCD3 and HD800. It's perfectly neutral, not almost. You only need to correct treble a bit in order to achieve ideal FR graph.
Perfectly neutral phones do not exist... And if I feel that I have finally heard one, I would definitely not shout it loud out without having objective arguments in order to support it.
This only prove that what is neutral to one, doesnt need to be neutral to others... FR graphs are nice and all, but obviously we all have different ears... So they do not necessary represent what we perceive as "neutral"