It seems to me that whenever armed intruders break into a private home without warning, the residents of the home should have the right to defend themselves without question.
Which is why no-knock warrants need to go. The practice allows the govt to routinely infringe upon citizens' rights to reasonably defend themselves based upon the risk to the police of a rare situation, as you put it. It seems citizens' lives are less important than police lives, as long as we can say it might be a murderer that's the target of the no-knock warrant, when it's far more likely to be a small-time drug bust.
But thanks for bringing up the rationale that will be used to kill the bill in the Senate.