I say just keep the animation and fix it, so when you slide your knife into him he will actually die.
People who run around try to knife others for tags are just selfish non-team players. Waste no time just shoot. Knife is the last resort or in close combat situation.
Thats the problem, knifing is an absolute horrible last ditch attempt in a CQ situation. Because last ditch effort means you are under heavy fire, and even if they do fix the registration, they will never remove that window of time that you can die as you reach towards you target, grab him, and start moving the knife towards them. Using the knife as a last ditch effort in BF3 just gets you killed. And fixing some buggy knifing will go a small ways, but not all the way. It's a crappy mechanic, and theres other ways they could imrpove upon knifing if they feel Rambo knifers are still a problem.
Which that brings up the other side of the argument. You can be killed as you are moving the knife towards your target. But the intenetion of the system is, after you have that knife in your target, you are now Superman himself. You are absolutely invincible. Damage stacks on you, but you will not die until you have finished killing that man. And so many times have I had to wait for a knife to end to even see if I stacked on enough damage. And I wait because theres been times I assumed they were dead, and I proceed on only to be shot or knifed by the target I thought was dead (but you can't kill Superman). And that most likely won't change either, they can't give you a super sweet cinematic knife if you can be killed at any point during it. It's overall a crappy system, and thats just for knifing, I'm going to continue my rant of cinematics to jumping now.
Explain how awesome it is when you are running down a slightly incline that you press jump and your solider plants his hand on an invisible wall and vaults over it? Or explain how awesome it is when you want to jump into a yellow garbage bin, but you can't you just sit there in pogo, after a few jumps you get irritated, keep slamming on jump, then just get shot in the back and die, because you were trying to leap into the damn thing for cover, but you can't trigger the damn cinematic.
I'm sorry, you can't convince me cinematics should stick around, especially with an arguement only based on rambo knifers. It's plenty possible to knife and play with teamwork, I did it all the time in BC2. It allowed me to get on flags and cap them without appearing on the minimap by firing my gun. And if people truly listened they could tell I was there, many times I would be walking around then hear a curdling gasp of a dying man being knifed, and then I knew someone was out for blood and was close.