So I'm going to bump my own thread since the answer to my first question clearly is 'no'.
I stay in Hamburg quite a lot but never tried the Sofitel on Alter Wall until last week (I usually stay at the Louis Jacob). It was a bit of a last-minute booking and I needed to be in the city centre early the next morning; I had arrived late at night (following a flight delay) so made no use of the spa/pool or any other hotel facility.
I had booked the cheapest possible room and was given an upgrade to a junior suite on the second floor at check-in (Platinum status).
The room was quite nice and I would have enjoyed spending more time in it. The view was on one of the canals that run between the Alster and the Elbe. Here are some pictures I snapped with my iPhone (excuse the quality of the pictures; I should have turned off the bright lights). I'd certainly stay here again.
A view towards the desk and door. Slightly strange that the door is to your back when you are working, but much the better view this way.
The bed. Very comfortable.
Another view of the bed.
A view into the room from the bed area.
Overall I prefer the rooms at the Hyatt, but the location of the Sofitel (that's also the case in Berlin!)