My experience in this area is limited, please excuse my ignorance (fill me in where necessary :-) --
I've not been a very active club member, belonging to AMCRC spradically (I keep forgetting to renew!) and AMO for about 10 years or so. Ive attended two nationals, and a handful of local meets and very few non-AMC events, with my car-of-the-moment.
Other than my Gremlin, which was a very-close-to-stock restify, I'm pretty much a fiddler/customizer. My cars are rarely stock. They correspondingly do poorly when judged. I know this, don't really care (the judging fee I look at as paying for a super-choice parking spot, worst case :-)
I know a lot of people are in this same boat. Plus, increased scarcity of parts means people are doing non-AMC engines, non-AMC parts here and there, etc.
I know AMO has a "non-AMC powered" class experiment. Is there any thought to an "open" or custom class or classes?
I can see how this could look like a "slippery slope" issue, where more and more non-AMC AMCs dilute the real ones at events. I don't think this would happen though, I think it might do the opposite, over time.
First, AMCs on the road is better than not. The hot-rodded bathub Americans are a good point. They are reasonably desirable cars in their own right, with some interest beyond AMCers, especially converts. In decent running condition, they are probably already past the "cheap hot rod chassis" price to begin with. Non-running cars don't always get saved, and waving a magic wand to make them invisible to hotrodders would mean they get scrapped, not saved.
Second, it could mean that stock judging classes would have an "out" for really nice but non-stock classes.
Third, first-time AMC owners (or thinking-about-it) are daunted by the utter lack of parts. Imagine playing with early 60's chevies, then switching to even "popular" AMC chassis -- it's shocking. Custom AMC classes could be a bridge over this gap. It won't stop someone with a sawzall from jamming a 350 into an American, but clean non-hack conversions seen, documented and otherwise covered at an AMC event would be encouraging, especially with AMCers knowledge of swappability.
The AMC 8's are really nice engines with good performance options; even the six is a great engine. Non-AMCers might like the chassis, and have no problem with body, trim, interior, accessories, etc but be utterly lost and very wary with the engine. All-or-nothing isn't very welcoming; plus there's ten times as many non-AMC car nuts, new ideas on running gear adapatation, interchange, etc wouldn't hurt (and would be in line with AMC factory behavior :-)
Umm, a big point as yet unspoken is, we need more first-time AMCers. We don't want to end up like the Shakers.