For sure the whole thing is a complex area, mystique and not.
It's pretty clear that (for many years) I have been laboring the point that even amonst "similar" fins (ie: slalom) that typeX 32cm does not equal typeY 32 cm, and that in the end it comes down to a significant number of variables (inc rider style, as well as sail tuning, local conditions) that really make the difference between good and great.
Yes, agree, these are the micro level details - but what most here want.
Granted, there are some customers who simply require the macro knowledge (29 vs 36 etc) - although on average the guys looking for fin tuning info on these forums are more often seeking the micro tuning aspects (the "pro" level details found only by endless hours of on water time, racing, testing and comparing - something that is difficult for many normal customers to achieve but likewise welcome knowledge to share.) Yes, to some extent adding area specs to the dimensions could help (although a quick test of a Drake70NR with a similar area Drake40 Shallow will demostrate that area alone does also not do it). OK, macro example, but you got the idea. FW fins for F160? all 70cm, all similar area -but performance differences are quantum. Undertsanding could easily be described by non pros as mystique. Next one can be wave fin vs slalom (such as are both possible on say ST104..)
For the discussion, we had some years ago a very detailed "fin matrix" in preparation, it became a bit of an obsession to deliver the info accurately. In the end, it became too complex to be practical and precise, and, well, here we are..
No, doesn't mean it was a failure. More a work in progress
Cheers ~ Ian