The big problem with Crouch is that his heading technique is APPALLING (when it comes to efforts on goal). Literally, I cannot think of a worse header of the ball that has played football at the level he has. I'm convinced it must be because when growing up as a kid he never had to jump to head a ball, so he hasn't learnt how to do it, he always kind of, well, stoops his head at the ball and lets it bounce off him. Sometimes he balloons it over the bar because he's just heading it off the top of his bonce rather than actually putting a leap in so he can direct it down with his forehead. Yes he has scored a few with his head but he should have got a truckload more, so many tame efforts you see from him. It kinda works out ok for knockdowns but it is not the right way to trouble the keeper.
Compare him to someone like Cahill, who must be giving away like 8 inches to him (ooh err missus!), and it is almost embarrassing.