Although I have stayed there several times over the past year or so and may do so again (but only if its cheap enough), I really must agree with you. As I have written previously, the rooms are quite unexceptional and the overall ambiance is indeed cold and impersonal. It is sometimes possible to secure an upgrade to a suite but only if you are staying just one night. Regarding their treatment of diamonds, I was once nonchalantly told by the staff that the NY Hilton treats diamonds and golds precisely the same, which is usually indifferent.

Just in case you have not stayed there before, the Times Square Hilton is a much nicer property, staffed by warm and friendly folks who seem quite willing to upgrade both golds and diamonds. Its only flaw is the lack of an executive lounge, although from your description of the current condition of the NY Hilton's lounge, that may not really matter very much. Especially after the loss of the Millennium Hilton downtown, NYC actually boasts very few HiltonHhonors properties whereas Starwood now has quite a few hotels and the list is growing.