As the originator of the "Fidelity point" concept I'm not exactly a disinterested observer but I continue to think we missed the boat by not utilizing them.
It's more than just missing the boat, I think. Not using fidelity points, you have absolutely no other defined mechanism for *any* deviation from the original, including slapping navy blue paint on an Infinity and calling it a Nobler. So far no one had done it but there would absolutely no sanction or recourse to stop it in the rules. I don't think it's a pressing issue and I have pointed out the issue to people who care about Classic and they haven't been too concerned, but to me it is a simple matter to correct, and maybe it should be corrected before it does happen, thus avoiding a possible "incident" rather than waiting until it happens.
Moreover, not including the engine in the fidelity points certainly obviates any purist arguments about how it recreates an era. People don't put Aero-Tigers in their Noblers because they can't come up with a Fox 35.
I have heard Peabody's argument a lot - we don't know how to judge it, so we don't use it. I would suggest that's only because people are overly worried about "hi-fi" ing it. I've done fidelity points several times and had no particular problem with it. If nothing else, just use a 5-part scale
0 - Infinity painted blue and called a Nobler
5 - modern engine or electric, and/or large intentional deviations from design for performance enhancement
10 - Modern engine and prop or electric, airplane about right shape/size but modern finish and construction
15 - Modern engine and prop, airplane looks like 1959
20 - looks like Billy flew at 59 NATs
We could have many happy arguments about whether the first three shold range from 10 to 20 or 17 to 20, and that sort of thing. All you have to use is your *judgement*, and it takes a 10 seconds an airplane.
Brett