I personally think bayonets and/or melee striking would be a great "Next Gen" idea. Since there is already weapon collision w/ the walls, players etc I don't think it would be that big of a stretch.
IMHO, I would like to be able to have a melee strike for my primary weapon. Just the option could be neat. Personally, I wouldn't charge if I ran out of ammo, I would draw my pistol.
I use my knife only for silent kills, and even then your dreaming if you think the guys not going to team chat where you got him.
My feeling is, with this issue as well as 'more weapons' etc, I don't want it for necessedy, I want it for style
Also, if I'm able to knife someone, I don't mind having to double tap my "1" key, I'll leave my pistol on Quick Action.