This.

Sellers are able to entirely replace the product page with a completely different product. Give the reviews a once over to avoid getting something you think is good quality.

Yup, and that's essentially what I'm looking for. I read critical reviews, positive reviews that don't seem like shilling, and maybe a few recent reviews.

It would be even better if Amazon got their act together and penalized companies that introduce significant changes to the same product listing. For example, Wi-Fi dongles sometimes change the Wi-Fi chip, which changes the performance and compatibility. I've read reviews on exactly that type of product and chosen a different one because the replacement was worse than the original.

I just don't trust Amazon listings, and it has saved me enough times that taking the extra effort is worthwhile.