Heres my two cents:
Ok, no they are not cheating, nor will they ever be.
This is what they do IMO.
The settings take a lot of 'distractions' away. They make it so your screen doesn't jumble as much when nades are thrown, your character seems to be level at all times rather than the rolling of his arms which he is constantly doing. also when getting it your screen doesn't jumble as much.
Also, some of these settings (which are popular from theforce posting them all on that website that was recently posted here, who is also amd bill or codeofsilence correct?) . The settings ALSO make it appear that your shots are 'tighter' due to fov. The fov stock is usually increased so that you can see more on your screen (hence you can see more on your left/right and also things look 'farther away') When things look farther away, your shots are look tighter etc.
Do I think this configs help you as a player? Yes - Very - Much - So. I use my own config (with the stock pitch/roll/yaw/speed settings) usually, but when I know i'm going to be playing against someone tough, I switch to the 'tweaked' config.
Because I do much better, I'm not as good as Yang or riskyotter or jammer, but I'm nothing to sneeze at. I also made a demo of these changes and how they reflect gameplay, but I'm too lazy to avi the whole thing and edit the avi to show points of fire and blah blah blah blah blah..it was a good idea when I started it though :P
p.s. this isn't considered cheating
-Mattimeo