Damn, you made me go back and re-read when I was all sure of what was in that article. I could have sworn that this charge mechanic applies to all units, not just cavalry, but obviously cav was the main focus back when the game was out. I certainly can't prove this, it's just what I recall.

You're right on though with the foot troops. It almost seems to me to be a rock-paper-scissors game. If you single click charge with foot units, you'll get that delay, and if the opposing unit double-click charges they'll just keep plowing on and you'll lose all momentum and get hammered. If you double click then you'll (theoretically I guess, I'm still assuming the same mechanic applies) get the full charge bonus. Wonder if anyone else can jump in with the official word, now that Foz mentioned it I'd really like to know if that's the case or not.