I used Albert's Texture Patch 2.0 when I played RE4 PC. He basically took the Game Cube textures and ported them over, something CAPCOM could have and should have done to begin with.
http://z6.invisionfree.com/Resident_Evil_4_PC/index.php?showtopic=1631
I also used Albert's Textures Replacement Pack 1.0, which re-skins the menus and fonts of the game, as well as adds custom button icons to match your controller. Without it you won't even see KB key prompts in the escape scenes that use QTE.
Lastly, I used the MouseAim Patch 1.1, which has sensitivity adjust. You can even pan quicker using the A and D keys. With it I was able to win all the bottle cap challenges. You still get the dead zone effect due to the game having been made for gamepads, but this is basically the best anyone could have done via a mod.
This new HD version of RE4 better have at the very least this level of reconstruction. Hopefully they'll have gone the extra mile and given it a whole new control scheme made for KB/M.