No offense intended, however, I do not remember you as a particularly "scary guy", or do you transform ala Jekyll & Hyde once you step in front of class?
Doing kata testing and sparring tests in Shorin Ryu is different from Aikido in that in Aikido the "form" is more open ended and less determined. Thus people who do well in the more highly "structured" arts, may not have the same feeling of security in the more open-ended arts. (Please, to all of the Shorin Ryu people out there, I checked with my Godan in Shorin Ryu who is training here in Aikido. How he described his training was highly structured.)