"multiple items on the same page" - This is usually a positive, since it allows the user to easily look at color or size variations, there is a way to look at only reviews of certain variations

"mixed reviews and the unknown of which seller is more likely to ship a good product" - Being unsure of which seller is best also exists on eBay

I don't think Amazon's listings are confusing. You usually have size and color variations, and sometimes things like multi-packs. I guess that is subjective.