i also just got back from a 6 night stay at the hotel ( sunday to saturday). i probably stayed there 30 or so times so i am fairly well versed on the upgrade process. you will never get a towers upgrade. if you want the towers, ask for the points upgrade at check in or pay the 2500 points before you go. the best you will do is a deluxe harbor view room or an executive suite. they seem to think the harbor view is a better upgrade but i prefer the suite especially for a long stay.
regarding the amenities, they are basically the same in the towers as they are in the regular rooms. i spent the week before at the sheraton grand sukhumvit in bangkok which is a luxury collection hotel. granted the items you are referring to were better but despite things like the windowless platinum lounge on the 9th floor the sheraton hong kong works. maybe it is just like hong kong in that it is efficient but to a certain extent impersonal.
this stay one of my associates had some health issues that required medical attention and i can tell you that the assistance they gave her was absolutely perfect. one could not have asked for more and they have earned my everlasting loyalty ( unless of course the new w hkg has great rates and is a really cool hotel--spoken like a true flyertalker ).