But what’s with the half slice of cheese?
It’s a funny ole’ thing. Filet O’ Fish was a childhood comfort food from outings with my father. Then when I got my first paying job as a teenager it was at a McDonald’s and as a crew member I got to do a little bit of customization to my lunches (in the days when this was absolutely verboten for McD customers). So of course I added a full slice of cheese to my FoF. It didn’t work for me 
. Honestly surprising, but the half slice was a more harmonious pairing - a full slice kinda overwhelmed that little fish patty. Those fast food scientists may actually know their stuff.
Somewhat oddly, their own explanation is simply “that’s just the way they first made it in 1961.”
I hated my first, too, but mostly because it didn’t taste like a burger. It was nasty. I’d always eaten burgers at little independent places that my dad favored. The burgers at those places were great and not horribly expensive. We tried McDonald’s as a lark, and that was the last time.
I do remember the KFC BBQ chicken. I didn’t like the sauce, because, to me, it was excessively sweet. Like eating candied chicken.
The thing about many fast food burgers is that the burger ranges from mediocre to very good. But if you just ate a little piece of the patty, it may taste more like salt than big beefy flavour. Most are not so good, only a few are great.
Cheeseburgers are rarely overpowered by the cheese and adding a full slice to a fish sandwich would make little difference. I think it’s mainly there to make the upper bun attach anyway.
Even professional chefs talk about how a good burger has a patty which is just meat. “If you add spice or sauce or egg to the patty, you might as well be making meatloaf”. I do not agree, in any case everyone adds salt and probably colour, some add artificial barbeque chemicals and likely a plethora of others.
I think a hamburger patty should taste delicious on its own. You need to call it s meatloaf sandwich instead, fine, but that’s just semantics. No cheft hesitates to add all sorts if crap to fish to make a “salmon burger” taste better. Spices and sauces are what make good food grandiose.
I love a good beefburger, but rarely enjoy meatloaf. 
It’s perhaps not surprising that my tastes are different from those of a poster called dr_paprika. I have a string aversion to the entire capsaicin family, it and while i can tolerate a little paprika, it definitely decreases my pleasure in any food item it’s been added to. I am much more often put off by over seasoned food than by under seasoned food. As a child i had an extremely strong sense of smell and taste. I remember physical discomfort from sitting near perfumed ladies, or entering my grandmother’s guest bathroom with it’s lavender-scented soaps.
My senses aren’t as delicate as they were when i was a child. I even sometimes intentionally add a tiny smear of mustard to a sandwich. But even now, most of the strongly flavored foods i really like are main ingredients (mackerel) not seasonings.
I certainly speak for myself and not others. I am not saying I make my burgers taste like meatloaf, I do not. But if burger patties taste better with a few simple added spices, sauces like mustard or ketchup, and other ingredients not adding them out of an artificial purity is silly. My burgers are not usually spicy.
For a McRib, saucing the meat to hide its taste may or may not be an improvement. The meat by itself did not have a strong or memorable taste and it is many years since I have had a McRib.
If you’re avoiding adding that out of a sense of purism, sure, that’s silly. But adding eggs and stretchers and stuff to a burger itself changes the texture and feel of the burger to something different than what I expect from a burger. Even mixing salt in with the meat instead of putting it on top when you cook it changes the consistency of the product into something more like a sausage patty than a burger. I don’t add stuff to the interior of my burger because it makes something that is not what I want when I want a hamburger. For me, the texture of the meat should be somewhat airy, for lack of better word. It should not have the bite a sausage has (which is what happens when you intermix salt with it and work it a bit, and even moreso if you add egg to it.) It should stick together, but very gently break apart when you bit into it, with no “spongy” resistance. Put all the seasonings you want on top of it, I’m fine with that. I like to add some Slap Ya Mama on it or just a simple salt-pepper-garlic powder. But to maintain the texture I most associate with a good burger, it needs to be handled minimally and nothing should be intermixed with it.
That’s fair. You can add lots of sauce and get something that you can’t easily grill or is not burgery. But that’s not an automatic thing - you can add modest amounts of stuff without much changing the texture. You do not have to add egg, or a whole egg. And IMHO adding onion or feta cheese or bacon makes any small changes to texture worth it. YMMV.
Talking about the Filet O’Fish (which has an Irish name, gotta appeal to the Catholics), I remember being served one without cheese as a mistake. (Drive-thru, naturally.) It does suffer. That cheese gives just a bit more saltiness and creaminess, it just seems dry and bland without it. Despite the tartar sauce. That little half slice matters.
I think it would be even better with a full slice, but I’m no sandwich scientist.
Now, mind you, there are “hamburger-like” things that I make, like the Serbian/Balkan patty called pljeskavica, where the texture is purposely denser and springier, sometime so much so that some recipes call for the addition of a small amount of baking soda to help achieve that, and in those, you can add onion or garlic to the patty and you knead a good bit to get that texture. That’s fine. It’s just not a hamburger to me.
The idea is to add just a little bit of things that make a difference to the flavour while minimizing mixing and kneading and texture changes. It’s a sweet spot. It’s not like a fast food burger lacks added salt or whatever chemical chimera is needed to make Burger King taste and kind of look grilled, when it is microwaved.
For a time, I was a line cook at a breakfast/burger place. My trick for burgers was a splash of Worcestershire sauce, a tad of Lawry’s seasoned salt and black pepper. All on top.
Yeah. I like black pepper and horseradish for “heat” but no capsaicin peppers.
It goes on top of the meat, because, yes, it does make a difference in how it affects the texture. And if your burgers are bland, you are probably not salting enough.
You can see here how how you salt affects texture:
Worcestershire sauce is great in burgers. Salt, pepper, garlic powder, onion, dehydrated onion, just a bit of bacon, a little feta, scaled peppers, just a little bit of ketchup and mustard… I still think it a burger - the texture is not much changed. My meatloaf is much more complicated, with lots more stuff (modified from an ATK recipe) but opinions are like mouths. Disagree if you wish. Burgers with includeds (mixin’s) not exactly the same adding these things on top (fixin’s) - but good toppings are good toppings. A lot of taqueria stuff works well on burgers too. Serious Eats is right about most things - love “The Wok” - but I don’t have to agree with their definitions either.
Certainly, I’ve quibbled with them and, moreso, Cooks Illustrated before where I thought they (CI) just destroyed the spirit of an ethnic cuisine with their fussy and weird changes. I do seem to recall that very early recipes for hamburgers sometimes had chopped onions incorporated within the meat and perhaps the hairsplitting I’m part of is a more modern affectation. I do know that stuff like salt inside the meat does change the texture massively, as those picture (and my own experiments) show. It’s not a minor difference, but I can be picky about my food texture preferences (see the spaghetti thread about breaking it). Now whether 95% of people care, probably not, and for many, it may be an improvement for all I know (though people have asked me what my secret to good burgers was when it’s only just use 80-20 or fattier meat, add salt and pepper before cooking, and not much else. I seem to always get a furrowed brow, like I’m withholding some secret from them.) Do whatever works best for your tastes in cooking. That’s the joy of cooking for one’s self.
Honestly, I tend to quickly marinate (like barely) my ground beef in a moderate amount of Worcestershire sauce when I make hamburgers at home. Just an affectation I’ve had since I was a teen. Salt (lightly, because of the WS) and pepper on the outside. I’ve substituted (rather less) fish sauce a few times for kicks
I have had a very nice burger a friend made with a carefully inserted pat of compound lemon butter in the center, but generally I don’t go that complicated.
Salt makes a big difference to meat if given time to do so. I add it literally just before cooking as the last thing. If you cook a thin patty at four or five minutes a side, I think the effect of salting during cooking modest. Maybe I’m wrong. I’ll try it your way next time I do it and might be pleasantly surprised. Cooking should have an air of experimentation, that’s why Serious Eats (and often CI) are good in the first place.
Now back to McRibs…
It sounds like you actually do it my way, if I’m understanding you right.
When the salt and the meat sit around and have time to mingle, like when you salt it and mix it up, the texture changes. That’s just science and how salt and proteins react. Surface area salt has a different effect on the meat. As for McRibs, I feel like they’re all mixed together. They have a chewy texture I associate with that type of mixing of seasonings and meat.