Couldn't all these things happen fast enough that there are multiple primary things to look at?
Some random thoughts...
Has it really been that long since I've done two-man? Kelvin, I don't understand how you can say Lead is strong side and Trail is weak side unless you work in a system where Lead crosses the lane in two man. Is that the case? If not, don't the players and the play dictate this?
Are you guys saying you literally watch the flight of the ball? This is something that happens fast, but the only time I've ever heard of this is when I read where Reggie Miller watched the flight of his shots. Other than that, I don't know. If I shoot a ball I'm not watching the flight of the ball, I direct my attention to the hoop hoping it isn't one of those rare occasions where I miss.
Depending on the depth of the Trail and the location of the shooter, can't we have all of this within our view? If the shot clanks off the rim and goes up, obviously experience will tell us to check to see if it hits anything. I analyze many things, but I guess this isn't one of them up until now.
How many of those saying watch the flight of the ball have called a rebounding foul from Trail, before the ball has hit the rim? Actually, I'm not sure calling that a rebounding foul is accurate. These are often plays where a player gets pushed/pulled totally out of rebounding position.