Yes - I stayed there a few months ago. No way to avoid the parking charges. There are two separte buildings and the concierge lounge is in the building fartherest away from the front desk. Also, the "bay view" is a little misleading due to the distance from the hotel (unless you are staying in the main building). In regards to upgrades, I am a Lifetime Platinum and was not upgraded. However, it was a weekend and I believe there were several other large events at the hotel (wedding, class reunion, etc). My guess is during the week you should be able to receive an upgrade. The rooms are average for a spa property, but very quiet and comfortable. Finally, there is an awesome "mall" across from the hotel and plenty of walking space. Again, this is Newport Beach and even the malls are top shelf. All in all, I would give it a 3.5 out of 5 score.
I believe you have the Marriott Bayview confused with the Newport Beach Marriot Hotel and Spa which is located across the street from the Fashion Plaza mall. Everything you said about the Newport Beach Marriott Hotel and Spa is correct, but it is not the Marriott Bayview, which does have a view of the Upper Back Bay.
I've stayed at the NB Bayview property. It was very nice. Had great facilities and lobby, great rooms, and a lovely bay view. Costs a little less than the NB Marriott. It's true that you can't get around the parking fee. I believe we were upgraded. We reserved a standard room, and were given one with a bedroom, living room, two bathrooms and a bay view.