I think a compromise could be reached with a system that does not forbid or penalize arm variations, but limits how many times arm variations can be used for +GOE.
If the skater really wants to Tano all their jumps... fine, let them. But why not only give each arm variation a GOE bullet point once (or twice or twice but must be in combination, or one double and one triple... there is a lot of room here)? In spins you can repeat features but you only get the credit for a feature once... make tano/rippons the same.
You can limit features in spins and steps (and lifts) because there are three people working together to keep track of features and only features + whether the element meets the definition or not.
You can't limit how many times a GOE bullet point is awarded because each judge decides separately for each element and they have enough other + and - bullet points plus program components to keep track of, each on their own. Even if you wrote a rule outright forbidding judges from rewarding this particular bullet point more than X times per program, you'd never know who awarded it or didn't without requiring so much record-keeping documentation that judges wouldn't have time to assess everything they're assessing now.
Even if certain jump bullet points were taken away from the judges and given to the tech panel as features, you still might get some judges who are sufficiently impressed by well-executed jumps with variations to reward them more highly than they would have without those variations. (And there would still need to be at least 6 bullet points if not 8, redefined, available to jump elements in order to allow for +3 for jumps that excel in multiple areas.)
This way a skater is not restricted... they can choose whatever they think is best for them, but there is no incentive to tano everything so I don't think we would see as much repetition. If it was per variation, we might see more skaters trying more different variations, which I think would be welcome.
I almost might add the language to something like "arm variation that adds to the overall effect of the jump without diminishing quality"
This I agree with.
Maybe there should be additional wording written into some of the GOE guidelines, either as part of the bullet point itself or an added explanation below. E.g., for "varied position in the air / delay in rotation" (assuming that bullet remains the same within the list), the explanation could note something like "Attention should be paid to the quality, difficulty, and originality of the variation -- simple common variations weakly performed should not be rewarded. Variety of variations within a program and appropriateness to the music chosen should also be considered."
Or that last sentence could be adapted into explanations of some of the Composition component criteria.
You still would get different judges exercising their individual judgment as to what's sufficiently difficult or well-performed or original enough to reward or not, and we still wouldn't know exactly what each of them were thinking. But they would have reason to consider those aspects and not just reflexively bump up the GOE another grade every time a skater's arm goes up in a jump, if indeed that's what any of them are doing.
Putting that in writing would also give skaters reasons to attempt more difficult, more original, more choreographically purposeful variations in hopes of even more rewards.