Thank you for the constructive feedback to both of you!
We will test the connector with the Raspberry Pi A+, 2 B and 3 B as well immediately.
The connector should also work with these boards due to the identical pin header assignment.
After that we will adapt the documentation on the Kickstarter page.
@chickenHeadKnob: The high speed interconnect to the fpga is indeed a point
For my part, I don't like a "System Builder" or a "Design Suite" very much. I just want to code some little vhdl modules and get the data out of the FPGA or control my modules through an SPI. This was the main reason to connect the "simple" DE0 Nano board to my Raspberry Pi. For me it seems to be fewer pain in the ass. It depends on want you are planning to do with this stuff.
Thank you again for the feedback