Sigh....
I've had similar experience when I stayed there two weeks ago. The hotel itself was not full, but the GC floors were "pretty booked" due to some Mainland officials. AFAIK, the Mainland customers make up the bulk of the hotel's GC business now, and they pay good $$$$$ (full price of GC rooms at $2500, rather than a cheap corporate rate of $975!).
I noticed that service declined a lot at this property (well, I guess the attention to service also shifted to the Mainland officials -- e.g. 2 lifts being held at all times for private transport, GC concierge devoting all his/her efforts to them. While I don't have appropriate ground to complain, as upgrades are strictly due to "availability." Even though the last of rooms on GC have not been sold, I was told by the check-in agent that I would not be upgraded. Despite spending 10+ minutes trying to find a "nice room" for me, it's just a regular harbour view room, which was exactly what I booked.
In terms of upgrades and elite treatment, I can think of both Conrad and JW Marriott to be far superior to GH. It's also evident that at peak hours this hotel cannot seem to carry out the tasks property -- the staff lost all finesse and became frantic, while running around behind the long check in "bar." Seriously, I arrived at the GH from NRT, after my stay at the PH Tokyo, and I must say the check-in experience was night and day! While the PH was fully booked and didn't even have a desk for me to sit when I arrived, I was promptly asked to take a seat and escorted to my room to complete the check-in process. The staff was soft spoken, had (sincere) smiles constantly, and walked with finesse and good poise.
OTOH, when I arrived at the GH, the staff seemed to appear "efficient" by rushing and dashing hastily, most with expressionless faces. This to me is a clear sign that the GH is still stuck at a 4 star level, with no improvements, and no idea what "first class hospitality" means. The entire scene reminded me of a bunch of flies hovering above a spoiled watermelon.......
Granted, it's a much larger hotel than the PH, but with front desk staff running around (often with forced smiles that disappeared quickly after I turn my head), disorganized bell staff, inconsistent housekeeping, and incompetent concierge, I can say the only tangible benefit for me at this property is the cheap corporate rate. Should I be denied GC access AND any room upgrade after 10/01 like I would at the GH SIN, I will ADMONISH the GM and the check-in staff, and vow to NEVER RETURN to this property!