Kata--teaching model or bunkai model?

The sky is blue and my neighbor's catalpas are in bloom. The swallows are flying back and forth in the early evening, scooping up mosquitoes. I was sitting outside in an Adirondack chair with a glass of wine, having a conversation with myself.
     "So why do we do kata," I asked more rhetorically than conversationally.

     "To remember technique," I answered.
     "Well, there's got to be more to it than that. After all, you could simply write them down."
     "Perhaps they come from a time when people were mostly illiterate."
     "But why not just practice techniques? I mean, why arrange them in these particular patterns?"
     "I suppose each collection--that is, each kata, is arranged around a particular theme. Either that or they come from different sources, in which case we'll never know how or why certain techniques found their way into certain kata. Of course, if that were the case, you might expect a considerable amount of redundancy."
     "In that case," I answered, " let's pursue the first scenario--that there's a method to the madness or at least a theme."
     "Okay, but how would a kata show theme? I mean, I know some people have suggested that katas are based on animal movements--a dragon kata, a tiger kata, a snake kata--but how does that help in understanding kata? At best, it's sort of a cryptic and very Chinese way to describe things like that, almost like a codified and abbreviated way of describing things. I'm thinking there must be other themes that would be more useful."
     "Well, we could look for themes that were based on techniques that seemed to be repeated or prominent in a particular kata. For example, the pushing and pulling that seems to occur over and over in Seiunchin kata. Of course, to see kata this way you would need to accept that there is a natural link between kata and bunkai."
     "Oh, I think you might have to go further than that. I think if you look for themes in kata, you need to see kata as a collection of very specific sequences, combinations of techniques really, that explore different responses to similar scenarios. Variations on a theme, if you will," I suggested. "It might be that a kata is constructed to show different ways to respond to grabs or pushes, or it might show a single receiving technique (uke) with different bridging/controlling and finishing techniques," I continued. "Or it might be as simple as showing open hand techniques or the hands working in opposition."

     "So, not to get too far afield and too nebulous, let me bring it back to the original question then. Why do kata?" I felt like I was badgering myself. It's a beautiful evening, give it a rest a voice said in the back of my mind.
     "No," I said, though I didn't wish to offend anyone. "Let me rephrase the question. Why do kata the way we do them? Why continue to practice kata the same punctuated, stylized, and syncopated way we did when we first learned them? I've even seen kata done that way in Okinawa by very senior students. When you first learn kata, you are trying to commit something to memory, but once you have learned it why not use kata as a means to practice technique. Why continue to do kata as if it were a collection of still photo ops? Why the stiff, robotic movement? Why all the drama with the excruciatingly long pauses and the dynamic tension fit to burst a blood vessel? None of this is realistic. Once we have learned the kata, why not practice it, not to remember sequences, but to execute the techniques in the same way that we would execute them if we were actually using them in a self-defense situation?"
     "Let me get this straight," I said. "You are suggesting that we generally get mired in doing kata the same way we initially learned it, with the same pauses, the same stilted movement--what you might call 'the teaching mode.' Is that right? And what's the other way, 'the bunkai mode'"?
     "Yes," I said, and then I posted them on YouTube.
https://www.youtube.com/watch?v=ty6qvcX16Gs