If I ever sat on a psychiatrist's couch, I would definitely admit to having latency issues. I almost cannot use sat TV in hotels because the channels change so slowly.
Anyway, I got me a VGA 15-pin male-to-male cable at Radio Shack, and thinking about my issue while driving to and fro the store, I figured out the problem.
If the animation runs fine in Slideshow on the Mac when I'm just using the Mac, then there's no reason why it should run slow when outputting to the LCD. The machine simply doesn't care about the output, and the real conversation is between my clicker and the PPT program.
Then I realized: in default mode, PPT in Slideshow goes to presenter's mode, which shows two versions of the brief simultaneously: the current click and the next teed-up click. With a simply bulleted presentation, this is handy, because it gives you a cheat sheet for the next bullet at all times. Plus you can read off your notes in this mode, effectively giving you a poor man's teleprompter (the inventor of which just died).
But I don't need any of this: I don't stand behind a podium (it's the only way to induce fear of speaking in me); I have the entire many-hundreds of clicks memorized because my memory is overwhelmingly visual (forget your name, I can remember every click in a 1000-click briefing like a concert pianist playing a long piece by heart) , and I don't use any notes (I have the "text" pretty much memorized too as I hone it over talks; I don't actually ever write anything down and I never start with any prepared remarks, so I'm improvisational-seguing-to-canon that I can alter at will, depending on the audience).
The real problem is the dual visual representation of the brief: it's just too taxing for the computer to run two versions of my super-complex brief simultaneously. In the Office 09, you didnt' have the dual screens - just one. But I never used that either, because when I do use the laptop (meaning, look at it during a presentation), it's only when I can place it in front of me down low, so I use it as a visual feedback (nice conferences provide widescreens for that) so I don't have to turn around and look at the screen at all (except you must do it some, otherwise I feel it creeps the audience out). You want a full-screen representation for that.
So I disable the presenter's mode and voila! I can now run it on my home theater projector (looks fabulous) and when I factor in some reasonably gaps between clicks to account for my talking, there is no latency issue (even as I'm slowing down my animation and motion in this brief so as to slow down my talking pace for the audience's sake). I can keep my fancy transitions (which truly are beautiful), and I think I can add back some of the sound effects (which I am cutting back on).
To say I am relieved is a vast understatement. I built this new brief over many, many days. It represents about a hundred hours of actual labor but really 10,000 hours of presentational experience. It also totally exploits Office 2011 for Mac, which is - with all due respect - years ahead of Keynote, which makes it super-easy to have very cool looking briefs but does not come anywhere close to the animation flexibility of MS PPT. It's not even in the same galaxy. But it is impossible to create an ugly brief in Keynote--unlike PPT.