Gold is explicitly mentioned, too.
Yep, I was away from books before, but the sidebar from 4th edition (which included a section about the Allergies as well as one about having non-human metahuman forms) goes as follows:
While many European myths hold to silver as anathema to werewolves and the like, other regions and cultures with their own shapeshifter tales account for different weaknesses. The warek (leopard) shapeshifters of Africa’s Gold and Ivory Coast, for example, are known to be vulnerable and allergic to gold, while some wolf shapeshifters in Europe are vulnerable and allergic to toxic aconite.
Players may, with the gamemaster’s permission, exchange their shapeshifter’s Vulnerability and Allergy for another natural, uncommon substance appropriate to the paracritter’s local environment.
So Leopards from Africa are known to be vulnerable to gold, so it follows that Lions might be commonly the same way.
The part about them being able to have a different metahuman form (rather than all of them Shifting into Humans) was fully integrated into the rules for Shifters, so i don't see a reason why the alternate allergies shouldn't at least be acknowledged once they bring them back into the printed rules.
I still think that the added powers/weaknesses (Regeneration, Dual Natures, Allergy, Vulnerability) should be added back the the Shifters by way of a Sidebar (aka, All Shifters Have ... ) and then they could add the part about the alternate allergy options as a little subsection. I think that would be more effective than adding 4 more powers to each listing in the chart for Shifters.