What doesn't show up on the AMEX site anymore either (which they claim new people will still get) is the free companion. Doesn't show up on PLT or Reserve.
My revent experience out of NY has been that the upgrade lists are MUCH MUCH longer than they used to be before. Perhaps that is because DL is expanding here and people are beginning to realize it is a viable option.
Based on that, assuming the reserve thing is true - I have to assume it makes a difference. If you are a PLT on a K fare, I have to believe there are many other PLT on K fares...this should theoretically help.
I have the DL Reserve Card, but unless you have a buddy with the same status on the flight like the poster above, I have no way to see if it truly made a difference