I stayed at this hotel at the end of April. My experiences and observations are similar to
ACfly's.
I quite liked the convenient location—it took all of two minutes from the Central train station to the nice park outside the hotel and then the somewhat smoky lobby
. At checkin there was a similar conference about the Platinum status. The agent advised me that due to full bookings, pickings were slim for upgrades (I had booked a classic room); she then gave me what she said was the best non-smoking room she had on the second floor of the Palais wing of the hotel (the room was truly non-smoking ^ —not always a guarantee in Europe, IME). From here out my experiences start to diverge from the OP.
The room was charming and with tall ceilings, but small—in fact, I felt as though I was in a cube. The furniture and lighting fixtures were old-style (if not necessarily old) to fit with the theme of building and the heavy brocaded drapery (no Ikea look here
). The 'queen' bed was what we'd call 'full' in the U.S.A., with a rather (too) soft mattress. The rest of the furniture crowded the room significantly. The desk chair was adequate for short stints. My room was to the side, so there was no particularly attractive view to be had. Looking at the floor plan it would appear that most rooms on that floor are on the small end of the scale.
The bathroom was a single room, neither expansive nor overly compact with a generously-sized sink, a toilet, and a tub/shower combo that could use the curved rods that keep the shower curtain from invading one's space. Toiletries provided were house-branded, very generous (at 1.5 oz), and of decent quality—though each element seem to be of a different fruit/herb scent
.
The concierge was helpful and competent, as was the staff in general. I placed a room service order which delivered the wrong item
. I did not use the internet connection or TV (~20-inch CRT), nor did I check out the breakfast buffet (I left early). But I did take a peek into the gym for research purposes and agree with the OP that it is wholly inadequate.
...but, I did get a chocolate with my turndown service
In summary, I think this hotel is a welcome addition to our SPG choices in Frankfurt.