One thing I believe you're missing -- and a good reason why there are so many theories on ratings/sliders and which ones matter -- is the fact that EA does very little in explaining any of it.
Take SIE San Diego and what they do w/ MLB The Show, for example. There are numerous videos detailing what ratings
actually do, and more importantly, how they
affect other ratings. All backed up and verified by the devs in their own videos. Plus, they have an in-game strategy guide w/ over 20 pages worth of in-depth explanations/tips/game strategies for nearly ever mechanism and feature in their game. People don't have to theorize what sliders/ratings do because the devs have already explained, at one point or another, just how they actually operate.
EA, on the other hand, does not do this. Sure, they give us "Skills Trainer" -- but that's only rudimentary knowledge. All they do is show you
how to do something at a basic level and nothing about
why something works and
when to properly use them (i.e. "defend this inside run" with the plays we give you, while excluding any information on which situations would be best suited for such play).
Here's 3 different catch types. Use them for Aggro, RAC, and Possession catches. Here's a Spectacular Catch rating. Raise this if you want your receiver to make catches that look spectacular! Just run this 4 verts play if you wanna beat a Cover 2 (or whichever cover concept it's
supposed to beat).
Every single year, it's a guessing game w/ the community about what affects what. It's also mostly back to the drawing board, as well -- because when EA adds anything new to game, chances are it'll discreetly (at the least) alter another facet of the game. All of this is compounded by the fact that EA fails to provide us anything of substance they can't fit into 1-2 sentences, while leaving US playing 21 questions with each other.
How long did it take the community to figure out "one-cut" affected defensive players, as well? When have they ever explained traits such as High Motor, outside of a simple explanation that says "High Motor means players will make extraordinary plays he otherwise would'nt have made"?
You ask why people are so quick to take slider/content makers at their word?
It's because they have no other choice. People who create sliders/rosters up here do extensive testing before posting and detail these findings w/ an in-depth explanation. EA just gives you 1-2 sentences on how something works, and leaves it at that.
So, I ask -- would people be so quick to trust content creators about the mechanics in Madden and how features
actually work if EA would just explain it themselves,
in-depth, like San Diego does w/ The Show?