This ticket is to clarify the multiple use of the mouse scroll wheel, there's no reason to make several tickets. Many tickets on this but I will give you my logic :
1- Control : scroll wheel for adjusting differents stances of the character or set variable speed of vehicules. Don't need a combination with a key, the control is really important, and much better than Ctrl+Z (W) / S to adjust the stances, let the movement free. An interesting option is to have a variable speed with the character with a combination of key-binding and the scroll wheel ( keep Shift for sprinting ).
2- Set weapon : •Zoom
A combination of keys-binding and the scroll-wheel.
To let the left hand free for movement, don't have to use + / - or page up / page down.
3- Switch fire-mode : F + scroll wheel, F is a problem with grenade launcher, you can reverse the process without to pass with grenade and let another key to resolve this.
4- Switch weapon : key binding + scroll wheel, to resolve the problem of selecting weapon with menu. Good when you've got a launcher so 3 weapons ( rifle, launcher, pistol), can reverse the process.
5- Self-action / abstract-action menu : key binding + scroll wheel, key binding to open self action menu and scroll wheel to set it, select by clicking on the scroll wheel button the action.
Note self-action / abstract-action, so for context-sensitive ( ex. Open a door...) use spacebar.