I did today and needless to say gave them chapter and verse. With the capslock on for a phrase here and there. They needed reminding that their misguided changes are chasing customers (aka Sellers) away, which is no way to stay in business.
One suggestion, more of a scream, was complete seller protection from chargebacks if the buyer has NOT gone through eBay standard procedures first, or filed and been rejected. If return for refund hasn't been requested, INR filed etc, seller is protected from a credit card/paypal chargeback by definition. (not that eBay is, just the seller) Also transparency - direct contact between seller and credit card company or Paypal or whoever. Not that I think they'll do it, mind, but I'm willing to be pleasantly surprised.
Another: all phone buyers are required to read/view a written description before buying. It won't stop all of the problem buyers, but it would at least slow the rate down. A lot of times it's hard to even find the description in the App, and this would force eBay to be sure it could be read. If the seller hasn't added one, on their own head be it.
She who dies with the most toys still dies; when's the estate sale?