Just an FYI, and I really haven't seen anyone talking about this yet, but it appears as part of the language refresh in line with the new fee for additional cardholders, at least on the personal platinum, they have change the terms and conditions for the sign-up bonus to read:

"You may not be eligible to receive a welcome offer if you have or have had this Card, the Platinum CardŽ from American Express Exclusively for Charles Schwab, the Platinum CardŽ from American Express Exclusively for Morgan Stanley or previous versions of these Cards. You also may not be eligible to receive a welcome offer based on various factors, such as your history with credit card balance transfers, your history as an American Express Card Member, the number of credit cards that you have opened and closed and other factors. If you are not eligible for a welcome offer, we will notify you prior to processing your application so you have the option to withdraw your application." (emphasis added)

This is actually a pretty significant change and implies, at least on the personal side, that Amex is now viewing the Platinum card as a "family"; one bonus only, no churning between "flavors."

I don't know if the offer language on the Morgan Stanley card has been updated to match this, but the language on the vanilla Platinum reflects these new terms on both the application and in the fine print of the offer terms.

Regards