No one wants to read about how complicated the game is today, but the truth about playing the ball or the receiver depends on the quarterback, the route, what help you have coming from which direction, the down and distance situation, the game situation, the receiver's strengths and mismatches, what he's done on previous plays, what other receivers in the area are doing, the wind, the sun...
Truth is, playing in a defensive secondary today is like doing air traffic control at Hartsfield without a computer. A dozen factors to be weighed and reacted to within at most, two seconds.
Actually, it's worse than air traffic control. At least there, the plane is also hoping you'll be successful.
I can't imagine what subtle tricks receivers are using these days, especially now with back-shoulder pass routes. Way back in '68, as a HS freshman wide receiver, I was tricking DBs by faking looking at a pass coming my way--before making my corner or post break--simply because I'd read about Lance "Bambi" Alworth doing that with the San Diego Chargers. (The writing's on the wall when that early you're looking for mental tricks to make up for your dearth of speed!)
My ultimate football fantasy would be to just sit in and listen to each of the position rooms. I bet I wouldn't understand 20% of what they were talking about, the game has grown that complicated.