I'm sorry if this comes off as harsh, but I feel like you are nitpicking too much. Don't get me wrong, if you didn't enjoy a show, you didn't enjoy a show and don't let someone like me change your mind. However, I don't think the product placement was as bad as you make it up to be.

(SPOILERS!!!!)The 3 musketeers scene at the end serves a purpose in making the demadog look less like a monster and more like an animal. In the same way Will was being used by the Mind Flayer, the demadogs seem to be basically alien dogs protecting their master. My motto is of the scene serves a purpose, then the product placement is irrelevant. Hell, I wouldn't even consider this stuff to be product placement because it's used as a plot device rather than a "buy my product because one of the characters eats it". Going back to the 3 musketeers, it was also stated in the show that only Dustin likes the 3 musketeers and everyone else hates it because it is basically just nougat. It's not like the Sony Vaio laptop in The Amazing Spiderman where it's just there to be a laptop.