I am against the change and my vote reflects that, but were it to be implemented, I think the new behavior should be triggered only if the PC is wearing the amulet (identified or not) and Khelavaster should mention something and then die anyway. Then the player can try to give him one the next goaround. That is if the mad minstrel's hints aren't deemed enough of a hint in the right direction.
The "inconsistency" regarding Bart can be explained away. Khelavaster is in a weakened state so he cannot notice the magic emanating from the amulet if it's in your backpack. He can only recognize the item if it's up close. Bart, on the other hand, spends his days drinking and talking to anybody who will listen about his days in the arena, so he would be the first person to catch wind of the rumors about the PC becoming the new champion, and then he would keep his eyes peeled for it upon talking to you.