Sheets Slightly Wrinkled In Transit

I ordered two sheet of stamps and the seller packed them in an already used 10"x13" envelope with only one thin piece of cardboard instead of two (and placing the sheets in between them). Consequently, the envelope arrived looking very worn and the sheets sustained some small wrinkles that weren't present in the photos in the listing.

Would the appropriate course of action be to leave neutral feedback for this seller?

No. Contact him/her first.

GeoffHa: Why do you suggesting contacting the seller first?

Very good advise. With a bit of luck he might offer money back or even replace them.

Peter

We all make mistakes. If the seller relies on ebay for an income, casually given neutral or negative feedback could materially damage him/her whilst doing nothing for you.

Year ago I sold some Japanese stamps in Mini sheet form.The buyer opened a claim immeadiatly upon recieving them.I asked why?Then he sent a message saying there were some creases in the sheet.I did not want to bother,so I sent him a refund and said keep them.I said you can use them if you ever go too Japan.He gave me a postive evaluation

Certainly contact the seller and give him a chance to replace the sheets or offer a refund before leaving neutral or negative feedback. Also, if this was an ebay purchase, you have a right to return the sheets for a refund.

I agree, I would contact the seller first and explain what happened.

I've bought hundreds, perhaps thousands, of US issues on ebay. The few times I've had problems (maybe three or four?), I have raised my concerns directly with the sellers. Without exception, each one responded quickly and fairly, and as a result I've always left positive feedback. My ebay purchases have not involved higher-priced or scarcer stamps, however, since I think it is too risky to make such purchases on a platform such as ebay.

ebay gives as its official advice that you should contact a seller to try to resolve an issue before leaving -ve feedback.

As a buyer, I have mostly had positive results from this. Sometimes sellers give a full refund, tell you to keep the damaged article and just write it off.
Occasionally, sellers have outright refused a refund of any sort -- but these have been scammers. A few quick photos of the offending issues and an official complaint to ebay has resulted in a quick refund. In another case the seller continued to refuse the refund, but ebay adjudicated in my favor as the item was a clear forgery.
It doesnt matter a damn if the seller says "No returns" or anything like that.

These days I do much more selling than buying on ebay. As a seller, I really appreciate buyers getting back to me with any issue -- the last thing I want to get is -ve feedback as I'm sure my net financial loss from reduced sales is much greater than any refund I would have to give. Even when I think its an item where the buyer really doesnt have cause for complaint, I'm still happy to give a refund. (eg a guy who bought an old album with a world collection, then complained it had no GB stamps -- basically I guess he was thinking it would be better than what he saw in the 12 images posted, and was then disappointed when his fantasy failed to materialize)

For me absolutely the worst thing is people who leave bad feedback even after a refund. But, hey, its ebay.