I agree, chaoticset, that is true with an external art, as I am assuming Shotokan Kata is.

My experience is with Tai Chi Chuan, especially the Modified BeiJing variant of the Long Yang form.
My Sifu starts out all students in learning the postures of the form (about 30 depending on how you count them). Learning the entire form, just the external positioning of it, takes about 3 months.
However, the external postures are only a framework upon which to hang the real substance, which is the internal work that goes on while doing the postures: the movement and rotation of chi. Once the movement and rotation of chi is learned, one could almost do any external form, and as long as it is in balance, it would suffice.
Advanced students learn a 4 posture form that can substitute for daily practice of the long form, if the mindfulness and inner work are true.

More to the point: the specific repetition may not be necessary, but I believe that repetition of some kind *is* necessary to move the mind out of the (usually) stuck place it is in, in order for new learning to come in. Especially so, if the thing to be learned is to *replace* older learned habits (in this example, such as: carriage, balance, awareness).

In other words, I see the repetition as a kind of "rocking the truck to get it out of a rut" kind of thing.