Why can't I bind mouse 4? Why can't I bind the "hold breath" key for sniping? Who can comfortably use LAlt for that function? It's crazy that so many functions are hard coded and certain keys can't even be used. I have to use 3rd party programs to play the game comfortably with a mouse and keyboard, and I use the "standard" wasd configuration too.

Not sure why you can't bind Mouse4--I have it bound in my game. Do you perhaps have mouse software that alters how Windows sees that button?

I agree on the other points, though--they did a half-complete effort in one of the patches to open up keybinding a little, but many things remained hard-coded, like holding breath, lock-picking, exiting out of many of the menus, and secondary functions of keys like R and TAB not remapping with the main function.

I personally use F4SE to access and fix the hard-coded key functions.

I just want bash/power attack to be separate from grenade.

I have the http://www.logitech.com/en-us/product/corded-mouse-m500. Whenever I tried to use Mouse 4 (which is the rear thumb button) I get a message saying that the Mouse 4 key is "reserved". What does that even mean? Also no, I did not have any programs that altered how windows read that key. I do now though just to get it to open favorites like I wanted.

OMG YES! So many accidental deaths because of this! Why would that leave that hardcoded on PC is mind boggling!