First things first: The organization of the whole event was very professional and the organizers cared a lot about small, but important, details. They made sure every speaker felt as appreciated as possible. Usually a setup similar to the given situation should be the standard, unfortunately it is not. Even better that Heise Developer and iX magazine meet their reputation by providing such an outstanding experience.
One of the many things the event did right was catering. There was just always a good supply in drinks and foods. No one could complain about that. Also everything was arranged to simplify the get together. The special evening events did also contribute to the nearly flawless experience. The only thing that I did not like was the selection of some the talks, but this is something that will never please everyone. So casualties are expected here. Nevertheless, the distribution was great, such that I always could find at least one interesting session across all the tracks.
The ratio of participants to speakers was also great. I could talk to many other speakers, as well as participants. The observation I could make was that there is a general scepticism against HPC (for instance the computational demands and the tooling). There is also a common desire for simplified programming constructs, easy-to-use patterns and available bundles of best practices. The desire of course explains the participation in the event.
I don't know if a contribution like the presentation of the QPACE 2 HPC project would have been accepted in the recent years. This year the organizers decided to focus a little bit more on the HPC. I don't know how many people attended the novel Fortran track, but my guess is that the parallel conference will not focus on HPC again. There are many HPC conferences, and even though this one would be a great addition, I believe that most participants don't care about HPC and see their personal interests in more ordinary matters.
So in conclusion I've attended a conference that provided a careful selection of contributions tied together with a very professional organization. I would be happy to contribute again!