With the new changes to key wardens now dropping machines instead of keys and all acquired keys now turning into machines and the posiblity of ubers dropping more then one material and also all ammulets coming with a guaranteed socket.
With all of that I'm guessing helfire ammulets will become standard on every chatacter? Or am I wrong? I guess almost everyone is going to cube a ring and not an ammulet so it people were depending on an imunity ammulet helfire might not replace it but wouldn't another free passive be way more powerful then an immuity?
I think the fact that the machines are easily farmable now and that your guaranteed a socket really improves the helfire. I'm one that never farmed them yet so I haven't been burnt out of them like some have.
Like on Monk I'd rather have Arcane and/or Lightning Immunity over another passive, mainly due to how lackluster most Monk passives are. Or on my Dart Doctor for the same reasons.
With the changes to HF farming getting a decent or great amulet is definitely greatly increased. But the cube and how it's structured definitely gives more build diversity that keeps anything in the jewelry slot in constant flux. You "could" be immune to all one shot dmg by wearing and cubing Cameo and Xeph, but you might not have F+R and CoE, or RoRG etc etc.
Oh and even on T10, machines weren't a 100% drop, so that's something else to consider.