Please give us the option to bind "select primary weapon", "select secondary weapon" etc. to different keys.
E.g.:
1 = Select primary (rifle)
2 = Select underbarrel (GL)
3 = Select sidearm (pistol)
4 = Select secondary (launcher)
While the current system already offers option 3 & 4 it's not the same.
Pressing the key twice could also switch the firing mode.