You are able to see a blow coming before it connects and depending on your reaction time and training may well be able to deflect, block, or intercept that attack. There are in fact martial arts for which those things are a core part of the style so I don't believe the +4 after the attack is too terribly unrealistic nor would it be unbalanced.
I'd also like to say thank you to the folks that are responding the discussion so far is sounding civil and isn't getting out of hand. It's nice to be able to discuss things in that manner. Cheers to everyone and regardless of how the dice fall in the end I hope we have some happy gaming.