That is true, up to a point. A good 'keeper will instill a degree of confidence in the guys in front of him, that he'll deal with at least some of the stuff they miss.
Leighton didn't come for crosses much and when he did, he usually missed them, BUT he had McLeish and Miller to do that kind of thing.
I thought he wouldn't be replacable, but IMO Snelders was at least as good, if not better in some aspects - at least up until that hun prick smashed his face or maybe losing his bottle in the Holland germany game............
I think he was the last good keeper we had.