What information should be included in sales listings?

I agree with you 100%. Overused and often times on cases that to me have clearly been polished.

Although I value the effort to reduce unvertainty and imrpove the sales listing, the different kinds of listings makes the charm of collecting. Some are very accurate, some write very very long descriptions, some just present their watch with pics. I like the diversity despite some annyoing points like not telling the diameter, important information like the price between a bulk of pics etc.
I also believe one information to be important: The case diameter. Any other characteristics of the watch, I have to evaluate on my own. If someone says, the dial is original, I can believe the seller, but Imho I should do my own due diligence and have to inspect the dial. Same holds for the other characteristics.
And the non-disclosure of some characteristics in the description tells me so much about the seller... So I am in the no template boat.

I agree, but I am not sure that a sales listings template necessarily interferes with the learning process.

I think that a template that is open to interpretation would still allow for inferences to be made about the seller. But I acknowledge that there could be a trade-off between ease of access to information about a watch, and ease of access to information (inferred) about a seller.

I broadly agree. I think that there could still be diversity as the template would not preclude sellers from writing additional information. But it would certainly create greater uniformity.