I've called amex today... I currently have the card with the plus option and asked the lady what they can offer. She enumerated the things you get like the bonus segments etc... but I stated I don't need them as I already qualified for gold.
Quite a big spender on the card, I asked if she could make the same offer as for people who take the gold card starting from scratch (i.e. 20000 miles bonus) but she could not (I consider 140 euros for 20000 miles quite interesting).
I told her they were many people complaining so they'll take any complain and see if they should do something for existing customers... Wait and see