That's part of the game challenge is having difficult controls. You are supposed to be fumbling and having issues making those button presses, as it adds to the tension. The fact you are complaining, or anyone else is, says that it has been executed perfectly. If you don't appreciate that, it does not apologize. There is so much in this game, that, if not done just the right way, never works. Your fingers are supposed to be in some spazzed-out position executing some crazy maneuver...
LOL, reading this just makes me face palm. You're totally glossing over the fact that gamepads are better supported both via onscreen prompts and function listing in the control menu. So what then, only PC players need this fumbly jumbly design?
It's a simple case of poor PC support, and it's common with Japanese developers. Mikami did the same thing even with the mega popular RE4. They simply don't focus as much on PC, until they start getting flooded with complaints. Example, to execute a point and aim CQC in Ground Zeroes you had to hold RMB and Q down, then press an arrow key to issue the command you want. It was an almost impossible reach even for those with large hands. In The Phantom Pain they changed command selection from arrow keys to 1-4 keys, which are FAR easier to reach while holding down Q. They did that because after MANY complaints, they realized they f*cked up. They also changed the binoculars to being more steady when zooming. In Ground Zeroes you actually have to lower the DPI on your mouse because zoom is so squirrely. These are things that should be obvious in initial design.
No dev in their right mind purposely makes such controls pretty much unreachable for anyone with medium or smaller hands, or in the case of binoc zoom, too shaky without sensitivity adjustment. It simply wasn't play tested well on PC. You get enough challenge from the AI in a game like this without gimping controls. That is a very short sighted analogy. What you're implying actually goes against quality control and is oblivious to the inconsistency of control from one platform to another.
Anyway, for those playing on PC with KB/M, here's a guide I copied from a site that wrote a guide on PC controls for TPP, which attempts to pick up the slack left behind by Kojima and his crew of merry misfits. It does not however include some things, like the aforementioned point and aim method of CQC, and how it differs from that in Ground Zeroes.
Basic Controls:
Hold F - Allows you to go into first person, with no weapons drawn this will bring out your binoculars.
Hold Left Ctrl - Walk pace, allows you to move slowly.
C - Press C allows you to crouch, if crouched you stand. Hold C Allows you to prone, if prone you stand.
Mouse - Left Mouse Button (LMB) fires and Right Mouse Button (RMB) aims, nothing abnormal there.
Q - Allows you to call for help on the radio.
Left-click (unarmed) - Initiates CQC, and holding allows you to grab opponent.
E - Climb, get in vehicle.
WASD - Standard movement and vehicle control (W accelerate, S break reverse).
Space - With no weapon drawn you dive to the ground in the direction you are moving.
Tab - Press to bring up iDroid system, which is an all in one map, mission objectives and tapes playing device.
1 - Selects primary weapon, hold to modify.
2 - Selects secondary weapon, hold to modify.
3 - Selects grenade type, hold to pick type.
4 - Switches to night vision.
When the Controls are Fiddly
One thing which is worth noting is that the mouse does not work for the menus, not an issue as arrow keys or WASD keys work just fine.
The controls become fiddly when dealing with grappling or using the games inventory system.
Grappling:
To initiate a grapple you hold LMB, when near an enemy, with no weapon drawn. You now have a choice of what to do, interrogate, knockout or kill.
Interrogate - You press Q to initiate the interrogation, now you have to use the arrow keys to select the question to ask. But be sure not to let go of Q otherwise you will let go of the prisoner. When you have finished you questioning you let go of Q and quickly hold LMB again to get back to the initial options.
Knockout - Simply tap the LMB, it's slightly counter intuitive to let of the button, but not difficult to pull of.
Kill - Simply press E to kill and done.
Inventory:
You can do several things with the inventory, but every PC gamer knows how to switch weapons, so I am going to talk about modification of those weapons.
Holding down the key for a gun, which would be 1 or 2, allows you to do two basic modifications - remove/add light or remove/add suppressor. These use X and Y, I can imagine on a controller this inventory system working very well, but on keyboard it's a bit of a pain to start with.
iDroid:
Using the iDroid is easy when you get your head wrapped around it.
I found just experimenting with buttons, and looking at the screen allows you to work out what to do. It falls down with the system for changing pages, which use keys 1 and 3.
When you want to call for a helicopter, or go into Walkman menu you need to change the page. I found that using WASD, Space, and Escape (to go back) to be the most effective way to navigate through the iDroid.
This kind of thing wouldn't even be necessary if they'd paid more attention to PC support in the first place. The majority of consoles originated in Japan, and that's still where the mindset of Japanese developers are.