I, too, took a crack at the cpi (as more of a unhappy accident than a science experiment, but I digress), independently from Mr. Crouse with the standard 45-60sec wait, and wasn't a big fan.
My understanding (which could be entirely wrong) is that pre-infusion allows the coffee to de-gas (bloom) and absorb some of the water. Then, when you begin to brew for realzies, the water has already absorbed some of the solids and is primed for extraction.
Tepid water doesn't really extract very well; it either floats the grounds or sinks right through them, and there isn't much de-gassing going on.
Then you've got the problem of temperature... Say you're making a pour-over, and your pre-infusion is in the neighborhood of 50g for say 400-500g total brew weight, you've got 1/10th or more of your final brew at around 70F. The temp will normalize as you brew, but that first 100-200g of water is going to be significantly cooler than it ought to be (which is probably why the cup tasted flat and bland to me).
And, so long as we're interested in full disclosure, I'm on 2 cups o' drip, 1.5 shots esp (1 was bad and I didn't finish it), 1 cupping table, and no pain killers, so take my advice with a grain of salt or whatever.