Can Ntini consistently swing it both into and away from the batsmen? Which way does his stock ball go? I know it was only last summer he was here... I just can't remember.

Presumably a whole host of things can mean LBW shouts are rare. A quick list might start with:

{i} stock ball being short of a length / lifting sharply off a good length (over the stumps)

{ii) inability to swing the ball both ways (line too predictable)

{iii} absense of quality inswinging yorker / slower ball / reverse swing options (i.e. lack of variation).

I'm not sure if any of those help explain Ntini's record or not. They might be bling alleys and i don't pretend it's an authoritative / exhaustive list.. but sorting such factors out might be interesting...