To be fair, the Gold "upgrades" are yet another of those "deceptive" marketing promises from the same people that bring you the
"free" things.
You were not entitled to get the Tower rooms. It wouldn't matter if someone else at some point did. Seems like your expectation for the Gold level is a bit too high. At best, you are entitled to a "preferred" (does not equate to best either) room in the category you have booked.
Second, other than the Radisson (and one or two other hotels), Stockholm is the absolute worst European city for hotel/room quality especially given the price. And in that cess pool of hotels, the Sheraton fares relatively well but not as well as the Radisson across the street. So while I agree with the assessment of the hotel, I think the previous comments must be taken in the context of what Stickholm has to offer.
For another example, the Hilton in Stockholm looks like a Motel 6 compared to the Copenhagen airport Hilton and the treatment of elites is terrible. Yet, within the context of Stockholm, it seems like one of the tolerable hotels.