Advancing on the position of an invisible target is tantamount to walking straight into a blade. Being able to hear the location of the invisible target for is IN NO WAY advantageous. You can't see his blade, he CAN see your blade.

Now if you had a repeating pistol, say a revolver or automatic pistol, or rifle, then you could spray that area with bullets. But this is not the case. An arrow MIGHT hit the target if the target is unaware of the archer. Or there is no room to move. Or both.

This is obvious (or should be). An npc would not keep following a sound, swinging a weapon. Because he would just know this automatically...intuitively. And if the npc DID, he should miss you, and then die.

This is not just my opinion. It can be easily proven. If you don't believe it, I'll put a paper bag over your head, and stand back 10 feet, and say "now attack me". You will get swatted down. Not because you are blind. Because you can't see my weapon. The bag just went over your head, you saw the environment 2 seconds before. You know what it looks like. But you can't see what I'm doing or exactly where or how I'm standing. I am not static. I can move, the environment can't.

It just makes me mad every time my pure-Mage character goes invisible, and everything keeps chasing me, and hitting me.