There are obviously others that know more things than I do, but I thought that I had acquired some knowledge about the Ambassador desk since I have been at this level since the published program started (except for 2 years).
My first Ambassador was probably the best but she did not move to Austin, TX, when Starwood closed down the Lancaster, CA. office. My 2nd Ambassador was also very helpful and efficient (she chose to move from the CA. center to Austin).
I had also many conversations with people coordinating with the Ambassadors at various properties and what I was told is pretty much what you read on this board: not all Ambassadors are created equal.

My expectations are just based on the service that I have been getting for years from several Ambassadors.

This being said, I don't run after the Ambassador status. So far, I have spent more than half of the $ requirement and will almost reach the 100 nights by the end of June, but it might very well be that I will not have the $23K by December 31st.
Either way, the chances that I will only be assigned to a room in the future are extremely slim. I guess that after a certain number of years, nights and stays, you acquire a certain level of experience and know a number of people (some that you have known at a very junior level, then became GMs) that give you back what you have given with a long loyalty.
My experience is certainly not unique and there are also those that practically live in hotels.

I don't need restaurant or tour reservations or anniversary preparations or airport pick-ups from an Ambassador, just to be relatively efficient at securing suite upgrades, if those suites are available during my stay at properties that I do not know or where I stayed at only a few times. I really don't see the point of that status, that Marriott keeps making harder to reach, if the agents are just sending basic messages without giving some of the guest background and forwarding the hotel responses to the guests. Since I mostly stay at the same hotels (there are quite a few) in Asia, Europe, South America or the South Pacific, I really do not overload the Ambassador desk with work.
If the Ambassador perks are about the same as the ones given to the guests holding an over the counter Platinum card, there is no point of giving your loyalty to Marriott. It would be best just to give it to properties (managed or not by Marriott) that treat you well, based upon your previous stays.

Let's see how the new personal Ambassador service will be.