I have the same problem. This should have been fixed by now and I agree that it's completely unacceptable. Not being able to play because the game isn't responding to mouse and keyboard input is extremely frustrating. I don't underestand why this is happening at all, as all games require input handling, so surely you could just copy and paste code from BF3.
I would suggest commenting in this thread pretty frequently as there are new questions regarding miscellaneous issues among people who can actually play the game being posted every few minutes. Here are a few other threads with the same problem:
http://answers.ea.com/t5/Battlefield-4/Mouse-and-keyboard-not-working-ingame/m-p/1738363#M22333
http://answers.ea.com/t5/Battlefield-4/Can-t-use-Keyboard-Mouse-in-bf4-PC/m-p/1742357#M23652
3 threads and no proposed solutions.... I pre-ordered this game to get the close beta, couldn't play the closed or open beta due to this same issue, and now I can't play the official release due to the same problem.
One word: unacceptable.
I installed Windows 8.1 from Windows 8 and the problem was solved, I also have cloud disabled on Origin.
