I think what you find is a discrepency in the operable speed and size as opposed to the training speed and size of technique. By size I am referring to the size of motion. Most arts, I would argue all, at basic levels over gauge the size of motion in technique practice and under gauge the speed. An awareness of this discrepency is essential for learning, if the training is not already provided, to use any art in a more combative situation. Hence the reason for small fast sensitivity drills in the commonly thought of more combative arts. Combat speed is very fast and thus, by taking any technique or concept from aikido and performing it quick and fluid we can train to have the apparent effectiveness of other arts. Smaller size means overall time of technique is shorter. What this requires though is a well evolved understanding of the underlying concept in any art. One of the shortcomings I find with Aikido is the lack of attention to: skill of opponent, and progressive attack/counter-attack notions. For example, a Wing Chun practitioner is very adept at following lengthy attacks and counters without losing awareness, aikidoka find this difficult when the initial defense fails. However, a solid understanding of the principles, in aikido or otherwise, reveals that a counter and/or attack can be dealt with using a singular principle which flows through to answer multiple variations of attack, or a change in principle to accomodate progressive changes in incoming attacks. My best answer as to how to train this is: have opponents act like street thugs and not "on the mat" opponents, and develop training drills that have opponents attacking with multiple and varied techniques.
I have trained in various arts for a number of years and find this to be the template by which combat training occurs. In all an understanding of principles is essential than a progression to combativeness is made. Ultimately the way to train for the unpredictable and decisive nature of combat is to put yourself in unpredictable and decisive training situations. Which is what most of the combative arts do at higher levels. Higher levels being the key words! Also, these various principles are universal among all arts, just expressed in different ways. Never have I trained in an art where the phrase, "no be there, no be hit," did not apply. Some arts offer methods by which to take blows should they occur, but moving off the line of attack is a universal and virtually perfect defense.
Hope that made some sense... I apologize if my mind got ahead of my typing and would appreciate your responses...
Best wishes in your future training.