I am a beginner in Aikido (Just started this fall) in a class taught at the University of Kansas. After only a semester of training, our Sensei brings his Katana to class to practice ma-ai, or proper spacing. He uses the blade only in a downward motion and calls out the movement we are to make to avoid the blade. We've done it several times already with bokken, but the idea of the real blade adds a sense of anxiety to the excersize. Since the basic ideas of Ki-Aikido is learning to relax under any situations, I feel that the brade is an excellent tool for the class room.
This is almost exactly how I got drilled and ostensibly it was for the very reasons you mention. Any sensei worth his/her weight in rice ought to have plenty of tricks to make you uncomfortable without
a blade. You've got years of being uncomfortable before a live blade would really add value. Hell, just getting comfortable in my first gi took a few months. Stupid cheap drawstrings never stayed tied.
PS: I bet the blade is dull. Hope so at least.