I see what you're trying to do here Inks, and it's a mighty undertaking.
However, I believe you're getting carried away with the graphs. All a graph will tell you is how much of something is there, and no more. In my mind, your search for 'the ideal' is doomed to fail from the start for the fact that it simply does not exist. You argue for phones that achieve the true intention of the producer instead of enjoying the music, yet you fail to account for the most important variable in the equation: me and you. Music is supposed to make you
feel, not think. I had some time with the Etymotic HF5 last month, and I found it to be a spectacular IEM. However, while A/Bing with my ASG-1, I noticed that it couldn't quite produce violins with that rich timbre it should. My undergrad college had a VERY good music program, where I participated in music productions along with cellists, violinists, and pianists, so I know how these things sound. The HF5, despite it's great FR graph, simply couldn't pump out the euphoric sound that my ASG-1 did on Yo-Yo Ma's Goat Rodeo Sessions album. Another example is the GR07, which is notorious for it's treble spike. This intentional spike makes percussion and cymbals come
alive in songs. I'm sure that removing that spike would render the iem less special as a whole. The FX700 is also a flawed IEM by your definition. Yet it is also one of the most highly rated earphones around, and so are most members of the Final Audio lineup.
Like I have said many times, there is no perfect or ideal, that misses the point. It's about how true to the nature of the recording the IEM gets, the Phonak recently measured is a prime example. Is it perfectly flat? No, but it's pretty darn close, making it an outstanding performer, too bad the housing design goes against the sound intended as mentioned by Rin.
Anyway, the level of enjoyment for the individual and "feel" is more in the subjective realm, it will just make things even less tangible, that's something for the individual to conclude, can't share preferences because they're all over the place. I do enjoy my music very much, I don't try to look for details for casual listening, but that's beside the point. Knowing how a violin sounds like doesn't mean you'll specifically know how that violin recorded truly sounded in it's recording nature, unless you've perhaps have heard a reference loudspeaker set-up of that recording. I will have to check out the GR07's spike myself, IME with them, it seems to make it truer to the source despite risking harshness compared to a tamer presentation. FX700s go against a lot of how a recording was intended to sound, but it does sound special due to the wooden diaphargm and soundstage. It's a nice product but I wouldn't call it an outstanding performer, it falls flat at times because of the excessive bass and treble boosts. I feel a lot of these highly priced IEMs are rated highly because of their prestige not performance, the preferences of certain users shouldn't weight highly on accuracy which is the criteria here . I recently got the ER-6, released 9 years ago. It is notably more realistic than the newer, much more expensive EX1000, FAD S, C, SB and a bunch of other highly priced IEMs you can view in my IEM history list.
My point is that graphs are simply a part of the puzzle. It's like the political debate in the US where one side wants to cut taxes and the other wants to raise them. No one solution will work, but a cocktail of ideas will help paint a better picture. The same can be said about audio.
The beauty of joker's reviews is that he marries SQ objectivity with subjectivity in a nearly universal language. These two MUST come together to successfully convey what an IEM is all about.
The more subjectivity, the less tangible the rating systems are going to be, subjective ratings are good for personal preference, that's it. A universal rating system needs to have set rules and guidelines, with tools to measure data in the most objective way possible. Don't forget, that this isn't a 100% objective approach, subjectivity is there, it's inevitable, so there's a mix of both, but the objective needs a bigger stance to create a more grounded system.