This class looks interesting and similar to the binder/occultist but different enough to have a completely separate dynamic. I really like the mapping of the spirits to the harrow deck too, I feel it really helps it belong in the Inner Sea.
I also had some trouble understanding the point of compulsion as currently written, because 0-2 Influence mentions that it has no mechanical restrictions on how the medium interacts with the compulsions. At 3 Influence, the spirit must be taken again the next day, and at 4 Influence the medium loses control to the spirit. However, is there any penalty given to a medium at any level of Influence who completely ignores the compulsion? Do they gain a bonus for following the compulsion? It currently seems like the compulsion is half finished.
Will there be any way for the medium to trade out spirits known for other spirits at higher levels?
If the answers to these questions are in the document, then I'm sorry that I'm wasting your time with these questions, I only scanned it quickly.